I think I may be experiencing mid-semester burnout.
You seem to do work very hard. What do you do for fun, to clear your head? 
I hide in my room, turn my phone off and refuse to answer emails. I also walk, read, take photos, talk to my dog, play musical instruments and do cryptic crosswords and logic/number puzzles.
Today I am feeling a lot less on-the-brink-of-a-meltdown than I was yesterday, which is nice.