Moving object with x,y,z coordinate with arrows around object

Hello!

I have tried to make system where i can move object with x,y,z arrows. Same system how i can move objects in Unity editor. Here is image how that looks now. There is missing z axel in this point. Object moves like it should but when i rotate camera X button will rotate with camera and then it is totally wrong place.

Here is code:

     void OnGUI() {
         Vector3 pointWhere2 = camera.WorldToScreenPoint(gameObject.transform.position);
 
         buttonRect = new Rect(pointWhere2.x, Screen.height - pointWhere2.y - 90, 20, 50);
         if(buttonRect.Contains(Event.current.mousePosition))
         {
             if(Event.current.type == EventType.MouseDown)
             {
                 buttonPressed = true;
             }
             if(Event.current.type == EventType.MouseUp)
             {
                 buttonPressed = false;
             }
         }
         if(buttonPressed && Event.current.type == EventType.MouseDrag)
         {
             Vector3 mousePos = camera.WorldToScreenPoint(Input.mousePosition);
             float xPos = gameObject.transform.position.x;
             float yPos = gameObject.transform.position.y;
             float zPos = gameObject.transform.position.z;
             xPos = gameObject.transform.position.x;
             yPos -= Event.current.delta.y;
             zPos = gameObject.transform.position.z;
 
             Vector3 mouse = Input.mousePosition;
             gameObject.transform.position = new Vector3(xPos, yPos, zPos);
         }
         GUI.Button(buttonRect, "Y", levelData.arrowY);
 
         buttonRect = new Rect(pointWhere2.x+90, Screen.height - pointWhere2.y, 50, 20);
         if(buttonRect.Contains(Event.current.mousePosition))
         {
             if(Event.current.type == EventType.MouseDown)
             {
                 buttonPressed2 = true;
             }
             if(Event.current.type == EventType.MouseUp)
             {
                 buttonPressed2 = false;
             }
         }
         if(buttonPressed2 && Event.current.type == EventType.MouseDrag)
         {
             Vector3 mousePos = camera.WorldToScreenPoint(Input.mousePosition);
             float xPos = gameObject.transform.position.x;
             float yPos = gameObject.transform.position.y;
             float zPos = gameObject.transform.position.z;
             xPos -= Event.current.delta.x;
             yPos = gameObject.transform.position.y;
             zPos = gameObject.transform.position.z;
 
             Vector3 mouse = Input.mousePosition;
             gameObject.transform.position = new Vector3(xPos, yPos, zPos);
         }
         GUI.Button(buttonRect, "X", levelData.arrowX);
     }