I guess the topic title is a bit off, but I couldn't think of anything else.
The problem is, whenever I play, whether it be connecting to a server or hosting my own, the second I move my mouse to adjust my view, the player instantly looks up, and I cannot change my view. When I try to change it, all the player does is spin around in circles. I'm not sure what the problem is; I doubt it's a faulty add-on, because everything was fine yesterday.
I remember seeing a topic similar to this before, but I can't remember what that person was told to do.