Can't get animator to activate parameter more than once (Unity2D).

I'm having a problem with the animator in Unity 2018. On my script I try to call the same parameters more than once for a walking/sprinting animation (top down). I have attached the script below:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class Player_Controller : MonoBehaviour {
 
  //Rigidbody2D body;
  //float horizontal;
  //float vertical;
  //float moveLimiter = 0.7f;
  public float walkSpeed = 1.5f;
  public float runSpeed = 3.0f; 
  
  //public Transform target;
  
  private Vector3 targetPosition;
  
  private Vector2 mousePos;
  private Vector2 objectPos;
  private float playerRotationAngle; 
  public Transform targetPlayer;
  
  Animator anim;
  
  float angle;
  //Vector3 myRot;
  Transform myTrans;
  Vector3 myPos;
  public float rotationSpeed;
  
 
  void Start ()
  {
     //body = GetComponent<Rigidbody2D>();
     
     myTrans = transform;
     myPos = myTrans.position;
     //myRot = myTrans.rotation.eulerAngles;
     
     anim = GetComponent<Animator>();
  }
 
 void FixedUpdate ()
  { 
  
        Debug.DrawRay (transform.position, transform.right * 5, Color.red); //X
     Debug.DrawRay (transform.position, transform.forward * 5, Color.blue); //Z
    
    
    mousePos = Input.mousePosition;
          objectPos = Camera.main.WorldToScreenPoint(targetPlayer.position);
          mousePos.x = mousePos.x - objectPos.x;
          mousePos.y = mousePos.y - objectPos.y;
          playerRotationAngle = Mathf.Atan2 (mousePos.y,mousePos.x) * Mathf.Rad2Deg;
  
  transform.rotation = Quaternion.Euler (new Vector3(0,0,playerRotationAngle));
  
  angle = myTrans.eulerAngles.magnitude * Mathf.Deg2Rad;
  
                   //move object Forward & Backward
                  /*if (Input.GetButton ("Forward")) {
                      
                         anim.SetBool("walk",true); 
                         anim.SetBool("run", false);
                         anim.SetFloat("speed", 0.5f);
                         myPos.x += (Mathf.Cos (angle) * walkSpeed) * Time.deltaTime;
                         myPos.y += (Mathf.Sin (angle) * walkSpeed) * Time.deltaTime;
                         
                  }
                  else if (Input.GetButtonUp ("Forward"))
                  {
                         anim.SetBool("walk", false);
                         anim.SetBool("run", false);
                         anim.SetFloat("speed", 0.0f);
                  }
                  
                  if (Input.GetButton ("Shift")) {
                      
                         anim.SetBool("walk",false);
                         anim.SetBool("run", true);
                         anim.SetFloat("speed", 1.0f);
                         myPos.x += (Mathf.Cos (angle) * runSpeed) * Time.deltaTime;
                         myPos.y += (Mathf.Sin (angle) * runSpeed) * Time.deltaTime;
                 }
                 else if (Input.GetButtonUp ("Shift"))
                 {
                         anim.SetBool("walk", false);
                         anim.SetBool("run", false);
                         anim.SetFloat("speed", 0.0f);
                 }
                  
                  if (Input.GetButton ("Backward")) {
                      
                         anim.SetBool("walk",true); 
                         anim.SetBool("run", false);
                         anim.SetFloat("speed", 0.5f);
                         myPos.x -= (Mathf.Cos (angle) * walkSpeed) * Time.deltaTime;
                         myPos.y -= (Mathf.Sin (angle) * walkSpeed) * Time.deltaTime; 
    
                  }
                  else if (Input.GetButtonUp ("Backward"))
                  {
                         anim.SetBool("walk", false);
                         anim.SetBool("run", false);
                         anim.SetFloat("speed", 0.0f);
                  }*/
                  
                  if (Input.GetKey (KeyCode.W) || Input.GetKey (KeyCode.UpArrow))
                  {
                         /*anim.SetBool("walk", true); 
                         anim.SetBool("run", false);
                         anim.SetFloat("speed", 0.5f);*/
                         Walk ();
                         myPos.x += (Mathf.Cos (angle) * walkSpeed) * Time.deltaTime;
                         myPos.y += (Mathf.Sin (angle) * walkSpeed) * Time.deltaTime;  
                  }
                  else
                  {
                         anim.SetBool("walk", false);
                         anim.SetBool("run", false);
                         anim.SetFloat("speed", 0.0f);
                         //bool foo = anim.GetBool("walk");
                         //Debug.Log(foo + " for bool walk.");
                  }
                  if (Input.GetKey (KeyCode.W) && Input.GetKey (KeyCode.LeftShift) || Input.GetKey (KeyCode.UpArrow) && Input.GetKey (KeyCode.RightShift))
                  {
                         anim.SetBool("walk", false); 
                         anim.SetBool("run", true);
                         anim.SetFloat("speed", 1.0f);
                         myPos.x += (Mathf.Cos (angle) * runSpeed) * Time.deltaTime;
                         myPos.y += (Mathf.Sin (angle) * runSpeed) * Time.deltaTime; 
                  }
                  else
                  {
                          anim.SetBool("walk", false);
                         anim.SetBool("run", false);
                         anim.SetFloat("speed", 0.0f);
                  }
                  if (Input.GetKey (KeyCode.S) || Input.GetKey (KeyCode.DownArrow))
                  {
                         /*anim.SetBool("walk", true); 
                         anim.SetBool("run", false);
                         anim.SetFloat("speed", 0.5f);*/
                         Walk ();
                         myPos.x -= (Mathf.Cos (angle) * walkSpeed) * Time.deltaTime;
                         myPos.y -= (Mathf.Sin (angle) * walkSpeed) * Time.deltaTime;  
                  }
                  else 
                  {
                         anim.SetBool("walk", false);
                         anim.SetBool("run", false);
                         anim.SetFloat("speed", 0.0f); 
                  }
                   myTrans.position = myPos;
                   //myTrans.rotation = Quaternion.Euler (myRot);
  }
 
     void Walk ()
     {
         anim.SetBool("walk", true); 
         //anim.SetTrigger("Walk");
         anim.SetBool("run", false);
         anim.SetFloat("speed", 0.5f);
         //bool foo = anim.GetBool("walk");
         //Debug.Log(foo + " for bool walk.");
     }
  
  void OnCollisionEnter2D (Collision2D col)
  {
      if(col.gameObject.tag == "Walls")
      {
          //walkSpeed = 0.0f; 
          Debug.Log("Wall");
      }
  }
  
  /*void OnCollisionExit2D (Collision2D col)
  {
      if(col.gameObject.tag == "Walls")
      {
          walkSpeed = 1.5f;
      }
  }*/
 }
 

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