Keeping momentum with rigid bodies.

So i made a script for moving a rigidbody via the mouse, and a problem i seem to be having is when i let go it doesn't keep all the momentum, instead it just stops in mid air and then starts falling. I wanted to ask what i should use to move to the position of the mouse, right now i am using rigidbody.moveposition, but as i said that doesn't want to keep the momentum when the mouse lets go.

My script:

     float d;
 
     public Rigidbody2D rigid;
 
     public bool held;           //stores whether currently holding the object
     Vector3 localHeldPosition;  //stores where we grabbed it
 
     void Update ()
     {
         d = Input.GetAxis("Mouse ScrollWheel");
         if(held == true && d > 0f){
             transform.Rotate(Vector3.forward * d * 7);
         }else if(held == true && d < 0f){
             transform.Rotate(Vector3.forward / d / 7);
         }
     }
 
     void OnMouseDrag ()
     {
         //get mouse position
         Vector2 screenMousePosition = new Vector2(Input.mousePosition.x, Input.mousePosition.y);
 
         //convert to world space (on z=0 plane)
         Vector3 worldMousePosition = Camera.main.ScreenToWorldPoint(screenMousePosition);
         worldMousePosition.z = 0; //this is to make sure the position stays on the z=0 plane
 
         //if weren't holding last frame, remember where we grabbed it in local space
         if(!held)
         {
             localHeldPosition = transform.InverseTransformPoint(worldMousePosition);
             held = true;
         }
 
         //calculate the current position of the grabbed point in world space
         Vector3 worldHeldPosition = transform.TransformPoint(localHeldPosition);
 
         //calculate the 'error' - i.e. how much we need to move that point to fix things
         Vector3 worldDelta = worldMousePosition-worldHeldPosition;
 
         //fix it just by moving out object
         rigid.MovePosition(transform.position + worldDelta);
         held = true;
     }
 
     void OnMouseUp()
     {
         held = false;
     }

Another problem i had was that when i hold the object up in the air, drop it and then grab it while it is falling, then let go it keeps the speed it had when i grabbed it.

Thank You.