About power-ups...

Okay, so...

I've been trying to make a game where you are a comet. It's a platformer that doesn't use jumping. But I seem to be having trouble regarding the programing of power-ups. I need two power-ups (for now, anyways): Boosting (raising the speed of the player for a short period of time when he/she collides with a boost panel) and Invincibity (pretty self-explanatory).

My code is as follows:

 using UnityEngine;
 using System.Collections;
 
 public class BallController : MonoBehaviour {
 
     public float speed;
     public float initialSpeed = 10;
     public float topSpeed = 40;
     private float middleSpeed = 15;
     private float direction;
     private Rigidbody2D rigby;
     public ParticleSystem part;
 
     public GameObject suiEyes;
     public GameObject closedEyes;
 
 
     // Use this for initialization
     void Start () {
         speed = initialSpeed;
         rigby = GetComponent<Rigidbody2D>();
         //part.GetComponent<ParticleSystem>();
         part.enableEmission = false;
         suiEyes.SetActive(true);
         closedEyes.SetActive(false);
 
     }
     
     // Update is called once per frame
     void FixedUpdate () {
 
 
         direction = Input.GetAxis("Horizontal");
 
         if (direction != 0)
         {
             if (speed < topSpeed)
             {
                 speed += 0.1f;
                 print("speed x:" + speed + " speed y: " + rigby.velocity.y);
 
             }
             if (speed > topSpeed)
             {
                 speed = topSpeed;
             }
 
             rigby.AddForce(new Vector3(direction * speed, 0, 0));
         }
         else
         {
             speed = initialSpeed;
         
         }
 
         if (rigby.velocity.x >= middleSpeed || rigby.velocity.y < -16 || rigby.velocity.x <= (middleSpeed*-1))
         {
 
             part.enableEmission = true;
             suiEyes.SetActive(false);
             closedEyes.SetActive(true);
         }
         else if (rigby.velocity.x < initialSpeed + 1 || rigby.velocity.y == 0)
         {
                 part.enableEmission = false;
                 suiEyes.SetActive(true);
                 closedEyes.SetActive(false);
         }
     }
 
     void OnTriggerEnter2D(Collider2D coll)
     {
         if (coll.gameObject.tag == "Boost")
         {
             topSpeed = topSpeed + 100;
         }
     }
 }