Small issue with code, Help needed!

Basically I have the player moving across the screen when the game is started. The plan is to create a basic game that uses basic controls (tap&hold to sprint and tap-tap to jump, may add a double jump as well) to complete a platform style game.

I have a sprint countdown that triggered when the screen is pressed and held for longer than 1 second BUT in some instances the player will continue sprinting even though the screen is no longer pressed. It may be a minor problem, it wasn't what I intended.

Where have I gone wrong?

 void PlayerMover()
     {
         if (gameAlreadyStart == true) {    
             Vector3 pos = transform.position;
             pos.x += moveSpeed * Time.deltaTime;
             transform.position = pos;
             anim.SetBool ("running", true);
         }
 
         if (Input.GetMouseButton (0)) {
             sprintCountDown -= Time.deltaTime;
             if (sprintCountDown < 0) {
                 anim.SetBool ("sprinting", true);
             }
         }
 
         if(Input.GetMouseButtonUp(0)){
             anim.SetBool("sprinting",false);
             sprintCountDown = 1f;
         }
 
         if (Input.GetMouseButtonDown (0)) {
             if (!one_click) {
                 one_click = true;
                 Debug.Log ("click");
                 timer_for_double_click = Time.time;
             } else {
                 one_click = false;
                 Debug.Log ("double click");
                 if(onGround == true)
                     GetComponent<Rigidbody2D>().AddForce(new Vector2(0f, playerJump));
             }
         }
         
         if (one_click) 
         {
             if ((Time.time - timer_for_double_click) > jumpDelay) {
                 one_click = false;
                 onGround = false;
                 sprintCountDown = 1f;
             }
         }
     }