Touch gui texture buggy

I'm trying to press a gui texture on screen to allow the game to pause. Then presses it again and i unpauses it. I have written the following script which does the job, however its buggy and doesnt always work. Any tips?

 using UnityEngine;
 using System.Collections;
 
 public class pause : MonoBehaviour {
     
     public Texture2D texture1; // Inital texture for the button
     public Texture2D texture2;
     public bool paused = false;
 
 
     void Start () 
     {
         guiTexture.texture = texture1; // gui texture is made into button1
 
     }
     
     
     void Update () // If the screen is touched 
     {
         foreach (Touch touch in Input.touches)
         {
             if (guiTexture.HitTest(touch.position) && paused == false) // If the gui texture is touched then
             {
                 guiTexture.texture = texture2;
                 paused = true;
                 Time.timeScale = 0;
 
                 
                 
             }
             else if (guiTexture.HitTest(touch.position) && paused == true) // until the player stops touching the screen
             {
                 guiTexture.texture = texture1;
                 paused = false;
                 Time.timeScale = 1;
 
             }
         }
     }
 }