Why wont my character jump? (using rigidbody and addForce)

Hi all

Ive got what seems to be a quite simple question. For some reason i cannot make my character jump from the ground after i started to implement a logic that would prevent him from doublejumping.

Ive implemented my characters movement like this:

 public class PlayerController : MonoBehaviour {
     
     private Vector3 walkSpeed;
     private Vector3 jumpHeight;
     private float distToGround;
 
     // Use this for initialization
     void Start () {
         walkSpeed = new Vector3(4, 0, 0);
         jumpHeight = new Vector3(0, 12, 0);
         
         distToGround = collider.bounds.extents.y;
     }
      
     // Raycast under the player to detect if he is grounded
     private bool IsGrounded()
     {
           return Physics.Raycast(transform.position, -Vector3.up, distToGround + 0.1f);
     }
     
     
     // Update is called once per frame
     void Update () {
 
     }
     
     void FixedUpdate () {
         // Player Movement
         if (Input.GetAxisRaw("Horizontal") == 1)
         {
             rigidbody.MovePosition(rigidbody.position + walkSpeed * Time.deltaTime);
         }
         else if (Input.GetAxisRaw("Horizontal") == -1)
         {
             rigidbody.MovePosition(rigidbody.position + walkSpeed * -1 * Time.deltaTime);
         }
         
         // Player Jumping
         if (IsGrounded() && Input.GetButtonDown("Jump"))
         {
             rigidbody.AddForce(jumpHeight, ForceMode.Impulse);
         }
     }
 }

For some reason (checking with debug.log) my character never clears the 2 if statements checking if he is grounded and if the jump button is pressed.

The weird thing is. If i test on the if statements 1 at a time theyre working just fine.

Can anybody help me?