Why the healtbar is moving ?

I have this health bar script. Why, in the moment I move the camera, the healthbar moves with it instead of remaining over my spawned units. It works for gameobjects that are already in game, but has this problem for spawned units.

 public class AIHealth : MonoBehaviour {
 public Texture2D hpBarBG;
 public Texture2D hpBarCurrent;
 public Camera myCamera;
 
 private float offsetY;
 
 void Start () {
 offsetY=gameObject.collider.bounds.size.y-2;
 }
 
 void Update () {
 //I commented these 3 lines out when I tested it
 
 
 //Removed the 2 line here, they are screwing things up
 }
 
 void OnGUI(){
 Rect rcBg = new Rect(0,0,60,14);
     health h=(health)GetComponent("health");
 
 //Fixed this: added in the 1.0f to correct the calculation
 Rect rcCurrent = new Rect(0,0,((h.currenthealth)*1.0f/h.maxhealth)*56,8);
 
 //Just a simple clean up
 Vector3 point = myCamera.WorldToScreenPoint(transform.position + Vector3.up * offsetY);
 
     //had to add the substraction since my Y axis were revesed (
     rcBg.y = Screen.height-point.y;
 
     //do some ugly hardcoding so the bar is pretty and centered
     rcBg.x = point.x-30;
     rcCurrent.x=rcBg.x+2;
     rcCurrent.y=rcBg.y+3;
     GUI.DrawTexture(rcBg,hpBarBG);
     GUI.DrawTexture(rcCurrent,hpBarCurrent);
 
     }
 
     }