Unity 2D addforce problem

Hello, I am trying to move my character and I assigned AddForce to "d" but it just starts moving then it stops and I need to press key again to start moving. Here is my code: using System.Collections; using System.Collections.Generic; using UnityEngine;

 public class movement : MonoBehaviour {
     public Rigidbody2D rb;
     public float sila;
     public Animator anim;
   
    
     // Use this for initialization
     
    
     // Update is called once per frame
     void Update () {
         if (Input.GetKeyDown("d"))
         {
 
         
         rb.AddForce(Vector2.right * sila * Time.deltaTime,ForceMode2D.Force);
             
             Debug.Log("key pressed");
         }
         if (Input.GetKeyUp("d"))
         {
             rb.velocity = new Vector2Int(0, 0);
             
             Debug.Log("key released");
         }
     }
 }