Re-sizing objects in Photoshop - Photoshop has a mind of its own!

Since updating to the latest version of photoshop I've been having difficulty resizing objects. I draw a loose selection area with the lasso tool around the object and the usual blue line box appears around it with anchor points at the corners. I then use the anchor points to increase or decrease the size of the object - however, recently I've found that the object continues to increase or decrease in size even after I've detached contact from the screen with my stylus pen or the mouse. I'm not touching anything, but the object is still changing size, beyond what I would wish it to. This is really frustrating and makes it difficult to resize objects to the exact size I want. Why is this happening? Is there a setting I need to switch off so that the action stops as soon as I lift my pen away from the screen? It's absolutely bizarre and a problem I never encountered until I updated the programme. How can I make it so that I regain control over re-sizing of objects? Every time I re-size something it's like it just carries on without me.

If anybody has any suggestions I would very much appreciate it, thank you.