Mouse/Camera issues

Running MoP

Every time I try to change my camera angle with my mouse, the camera shifts dramatically up or down... I'm either looking at the sky or the ground, nothing in between. When I use the keyboard to move, the camera angle auto adjusts into 3rd person view and the keyboard buttons turn and strafe properly. But the second I touch my mouse, the camera angle glitches out again. It really make it unplayable.

I've set my mouse sensitivity to low... I've restarted the game. Any thoughts?

thank you much