Unity Character Controller for Mobile Device

I'm New in Unity 3D Programming, i just follow tutorial from survival shooter and try to add some mobile device joystick controller

why when i want to rotate the character with right joystick, when the analog is drag left (around 270-290 degree) and drag right (around 90 degree) the character is facing down, like image below.

Here is the code :

PlayerMovement script :

 void FixedUpdate ()
         {
            transform.Translate(Time.deltaTime * new Vector3(JoystickMove.instance.H, 0f, JoystickMove.instance.V) * speed * Time.deltaTime);
 
             Turning ();
 
             Animating (JoystickMove.instance.H, JoystickMove.instance.V);
         }
 
         void Turning ()
         {
             transform.LookAt(transform.position + new Vector3(JoystickRotate.instance.H, 0f, JoystickRotate.instance.V));
 }

and the JoystickRotate script

 public class JoystickRotate : JoystickMove
     {
         public static JoystickRotate instance=null;
         void Awake(){
 
             if(instance!=null){
                 Destroy(this.gameObject);
             }else{
                 instance=this;
             }
 
         }
 
 
 
     }

Hope someone can Help :D