Invisible hotbar, chat, and player name tags

Hello!

I first noticed the problem when joining a friend's world. My hotbar is invisible but still usable. Name tags above players' heads are missing, and I am not getting chat notifications that would normally appear in the top left corner of my screen. I have the same issue whether I'm on a server, or in my own worlds. I've tried restarting Minecraft, and my PC multiple times. 

Thanks in advance for any help!