What do I do to fix the trackpad? And why did this happen?

This morning I was using my Macbook Pro and the trackpad was working fine. It was doing the hard click and felt good. When I stop watching Netflix on my laptop the trackpad wasn't working so well. The click was softer and barley audible. It still works but it feels a bit loose. It bothers me a lot though. I'm going to take it to an Apple store to see if they can fix it. But I also want to know what might've caused this to happen??....