cycles render engine – Model appears jagged with no anti-aliasing in viewport and material view

I was texturing my model when suddenly all the edges of all models became extremely jagged, like anti-aliasing was turned off.

I checked my anti-aliasing settings in Preference (see attached) and they seem to be unchanged.
I’m not sure if I accidentally hit a button that caused this to happen.

In material view, the same issue occurs. And in rendered view in Cycles, it looks like a complete mess.

The last step I took before this occurred was attaching a OpenGL normal map to a Normal Map node, if that is of any help.

Any ideas on how to troubleshoot this further? Thanks!