Raycast hitting more than once

I've just noticed now that my raycast is behaving strangely, when I click on an object I want my ray to get the information of that object and behave accordingly, as of now it seems to multiply that ray each time I click on my objects.

Screenshot when i first click an object:

and heres the second time I click an object:

It has now output as if i've hit the second object twice, and this goes up by one each time i've clicked on a new object. Does anyone know why this is?

Here is my code:

 using UnityEngine;
 using System.Collections;
 
 public class selectObject : MonoBehaviour 
 {
 
     public bool isSelected = false;
 
     public string ballColor = "";
 
     public GameObject selectedBall;
 
     // Use this for initialization
     void Start () {
     
     }
     
     // Update is called once per frame
     void Update () 
     {
 
         playNextLevel ();
 
         if (Input.GetMouseButtonDown (0))
         {
             RaycastHit hitInfo = new RaycastHit ();
             bool hit = Physics.Raycast (Camera.main.ScreenPointToRay(Input.mousePosition), out hitInfo);
 
             if (Input.GetMouseButtonDown (0) && hit) 
             {
                 Debug.Log("Hit " + hitInfo.transform.gameObject.name);
 
                 if (hitInfo.transform.gameObject.tag == "redBall")
                 {
                     isSelected = true;
                     ballColor = "red";
                     selectedBall = hitInfo.transform.gameObject;
                 }
 
                 else if(hitInfo.transform.gameObject.tag == "blueBall")
                 {
                     isSelected = true;
                     ballColor = "blue";
                     selectedBall = hitInfo.transform.gameObject;
                 }
                 else if(hitInfo.transform.gameObject.tag == "greenBall")
                 {
                     isSelected = true;
                     ballColor = "green";
                     selectedBall = hitInfo.transform.gameObject;
                 }
                 else if(hitInfo.transform.gameObject.tag == "yellowBall")
                 {
                     isSelected = true;
                     ballColor = "yellow";
                     selectedBall = hitInfo.transform.gameObject;
                 }
              }
         }
     }
 }