Slow-Motion and Speed Boost - Jerky Movement Once Energy is Finished

I have my character moving on the y and x in a 2D game, my character is currently just a cube for prototyping reasons.

I have a sprint effect and a slow-motion effect, these are both activated by a button press, both last for a certain amount of time and then get regenerated for reuse.

I have got the general setup to a good level but when my slow-motion or sprint energy stores run out the movement does not entirely go back to normal if you don't release the buttons, slow-motion and sprint still has a slight effect on the characters movement.

Would be very grateful if someone could point me in the right direction:

My code is a bit messy so apologies!

 public var xspeed : float = 24; 
 public var yspeed : float = 24; 
 var x : float; 
 var y : float;
 var slowMotionBurnSpeed : float;
 var haveSlowMotion : boolean;
 var slowMotionAmount : float;
 var slowMotionRegenRate : float;
 var slowMotionMax : float;
 var slowMotionMin : float;
 var sprintBurnSpeed : float;
 var havesprint : boolean;
 var sprintAmount : float;
 var sprintRegenRate : float;
 var sprintMax : float;
 var sprintMin : float;
 public var sprintTex : Texture;
 
 function Start ()
 {
         haveSlowMotion = true;
         havesprint = true;
 }
 
 function Update () { 
 
 // *********** Sprint Button
 
 if ((Input.GetKey ("escape")) && (sprintAmount > sprintMin))
 
 {
 
 xspeed = 50;
 yspeed = 50;
 sprintAmount -= (sprintBurnSpeed*Time.deltaTime);
 
 
 }
 
 else 
 
 {
 xspeed = 24;
 yspeed = 24;
 }
 
 
 
 // *********** General Movement 
 
 x = Input.GetAxis("Horizontal") * xspeed * Time.deltaTime; 
 y = Input.GetAxis("Vertical") * yspeed * Time.deltaTime; 
 transform.Translate(x, y, 0); 
 
 
 // *********** SLow Motion 
 
 if (haveSlowMotion)
 
 {
 
 
     if (Input.GetKey ("space")) // Slow Motion
     
             {
             
             if (slowMotionAmount > slowMotionMin)
                 {
                 Time.timeScale=0.15; 
                 slowMotionAmount -= (slowMotionBurnSpeed*Time.deltaTime); 
                 }    
 
         // Ran out of slowMotion charge
     else 
         {
             slowMotionAmount = 0;
             haveSlowMotion = false;
             Time.timeScale = 1;
         }
         
 }
 }
     
 //******** Returning out of slowmotion
     
 if (Input.GetKeyUp("space"))
 
     {
     
     
     Time.timeScale = 1;
     
     }
 
 //******* power ups and true and false
 
 if (slowMotionAmount <= (slowMotionMax))
         
     {
     slowMotionAmount += (slowMotionRegenRate);
     }
     
 if (slowMotionAmount >= (slowMotionMin))
     {
     haveSlowMotion = true;
     }    
     
 if (sprintAmount <= (sprintMax))
         
     {
     sprintAmount += (sprintRegenRate*Time.deltaTime);
     }
     
 if (sprintAmount >= (sprintMin))
     {
     haveSlowMotion = true;
     }        
 
 
 }