OnCollisionEnter stopped working

 public void OnCollisionEnter(Collision col){
         if (col.gameObject.CompareTag("Player")) {
             Destroy (this.gameObject);
             Debug.Log ("Exp Earned");
         }
     }

I'm getting incredibly frustrated about this. I've typed this same code millions of times over in other scripts and no problem. It's attached to a sphere with a rigidbody and a sphere collider. I'm using ufps controller. It should work, but it just doesn't. I end up just on top of the orb. I have no idea what is wrong with it