Rigidbodies are disappearing when I click on them,How do I fix rigidbodies dissapearing when clicked?

Hello, as I am just starting to learn how to use unity, I am making a project to test unity which consists of a stickman that you can click and drag around the screen by the head. The problem is, the script I have on the head seems to cause the entire stickman to disappear when I click on it. I have the head as the parent of the torso and all limbs so that they move together, if that’s important. I followed a tutorial to make this, but they didn’t have the same problem in the video. Here is all of my code:

private float startPosX;
private float startPosY;
private bool isBeingHeld = false;

// Start is called before the first frame update
void Start()
{
    
}

// Update is called once per frame
void Update()
{

    if (isBeingHeld == true) 
    {

        Vector3 mousePos;
        mousePos = Input.mousePosition;
        mousePos = Camera.main.ScreenToWorldPoint(mousePos);

        this.gameObject.transform.localPosition = new Vector3(mousePos.x, mousePos.y, 0);

    
    }

}

private void OnMouseDown()
{
    if (Input.GetMouseButtonDown(0))
    {

        

        isBeingHeld = true;

    }
}

private void OnMouseUp()
{
    isBeingHeld = false;

}

make sure the camera’s projection is set to orthographic.
153480-capture.png

also, heres something even better. its the same thing but cleaner code.

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

public class DragAndDrop : MonoBehaviour                                                                                                       //make sure this ^ name matches the script name in the file explorer, young grasshopper
{

    private bool isDragging;

    public void OnMouseDown()
    {
        isDragging = true;
    }

    public void OnMouseUp()
    {
        isDragging = false;
    }

    void Update()
    {
        if (isDragging) {
            Vector2 mousePosition = Camera.main.ScreenToWorldPoint(Input.mousePosition) - transform.position;
            transform.Translate(mousePosition);
        }
    }
}

if you end up copying that, make sure the names match (the script and the scripts