Mouse issue....

My mouse went seriously wonky while playing Minecraft. Now, my mouse is responding fine to basic commands (like moving it) but not in Minecraft when my player just looks around at stuff for a second after I stop moving it. I tried checking the sensitivity but that was not the problem. My keyboard is working very well so that shouldn't be part of it either. Also tell me if you have encountered this problem and also if you found a way to fix it. Please.