I still need to undergo more tests to discover to what extent my anguish is mental vs. immunological or gastrointestinal (to say nothing of existential), but I am back to eating some things. Just crying all over a doctor and having a massive breakdown over the whole situation did wonders. It's amazing how much I wanted an authority figure to tell me that X was wrong and Y was definitely right and give me some rules to follow unthinkingly.
In other news, I was surprised by a couple writing-sample requests for some VAP-y things, and I sent them my articles. ... Meh. You'd be amazed how meaningless all that stuff seems to you when you are obsessed with being unable to breathe.
And just to continue my position as the poster child for why you should not go to graduate school, let me remind all those prospective grad students that we've been here, metaphorically, before.