Joystick issue in Unity 2d

Question

I've made a joystick script but it does not move the player i know that's not what i need :

   using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;

public class joystick : MonoBehaviour
{

    public GameObject Joystick;
    public GameObject joystickBG;
    public Vector2 joystickVec;
    private Vector2 joystickTouchPos;
    private Vector2 joystickOriginalPos;
    private float joystickRadius;

    // Start is called before the first frame update
    void Start()
    {
        joystickOriginalPos = joystickBG.transform.position;
        joystickRadius = joystickBG.GetComponent<RectTransform>().sizeDelta.y / 4;
    }

    public void PointerDown()
    {
        Joystick.transform.position = Input.mousePosition;
        joystickBG.transform.position = Input.mousePosition;
        joystickTouchPos = Input.mousePosition;
    }

    public void Drag(BaseEventData baseEventData)
    {
        PointerEventData pointerEventData = baseEventData as PointerEventData;
        Vector2 dragPos = pointerEventData.position;
        joystickVec = (dragPos - joystickTouchPos).normalized;

        float joystickDist = Vector2.Distance(dragPos, joystickTouchPos);

        if (joystickDist < joystickRadius)
        {
            Joystick.transform.position = joystickTouchPos + joystickVec * joystickDist;
        }

        else
        {
            Joystick.transform.position = joystickTouchPos + joystickVec * joystickRadius;
        }
    }

    public void PointerUp()
    {
        joystickVec = Vector2.zero;
        Joystick.transform.position = joystickOriginalPos;
        joystickBG.transform.position = joystickOriginalPos;
    }

}

But when i press down it disappear,and when I check it position it is 32666 in the x direction. Does anyone know why and how do i fix it?