Camera Follow Only Adjusting Yaw, Not Pitch

[sheldoore 0]

So I have a fairly interesting problem regarding the camera. As far as I can tell I didn't change anything to my game, but this morning when I started to play, I noticed that when I moved, the camera would only follow based on yaw, not pitch (meaning, it would snap to behind me, but if I changed the camera to be above me, it would just stay there). The equivalent setting in retail is for the camera to follow "Only horizontal when moving," however there is no such setting in vanilla. This led me to a whole bunch of forum posts and I have tried literally everything from deleting my WTF and config files, to creating a new account, to completely reinstalling 1.12.1 from another source. I don't have any addons so that isn't the problem and I've changed literally every key binding and interface option you can think of. Completely out of ideas and would love some help.

Thanks in advance!