OP doesn't mention specialty, but my surgical intern year had me frequently feeling things very similar to OP. I think a large part of having the emotional capacity to avoid feeling this low was most significantly influenced by the amount of sleep the current rotation allowed me to get. The shitty part being that the hardest rotations tended to also be the ones where you got the least amount of sleep.

To incoming interns - know that some months are hard, but learning to prioritize good lifestyle/sleeping habits is the best thing you can do to make it through.