What's wrong with my mouse?

It only happens when I play minecraft. It's almost like it has momentum. For example, I go to look left and it spins out of control and I end up looking at the sky. Or I go to look up and I end up spinning out of control and fall off a cliff. It also is like skipping. When try to turn or make fine movements lke you need to when crafting, the cursor is skippy. Sometimes it's like this all day, sometimes it's only like this for 30 mins or so then it fixes itself, sometimes it's not like this at all. I have no idea what's wrong with it.