Is this an eating disorder, or something else entirely?

Growing up, I never had much of an appetite; my mom took to calling me “Air Boy” at one point. I thought it was fine – after all, neither of my parents ever struggled with their weight, and I was a competitive runner.

Nowadays, it isn’t a joke anymore. When I’m particularly stressed or uncomfortable, my appetite largely vanishes. I just… don’t get hungry. I can force myself to drink liquid “food” or supplements, but almost anything solid triggers nausea and vomiting. I basically have to wait until I get so hungry that the need for calories outweighs the revulsion; I’m really only eating one small meal a day now.

I won’t post exact numbers, but I’ve dropped 10% of my body weight over the last 3 months, and I wasn’t a big guy to begin with. People have noticed, and I’m getting concerned comments from family and friends. I’m tired and irritable, and it’s making other, unrelated health concerns worse. I’m having trouble keeping up at work, which has never happened before. I’m running on caffeine and rage, and it’s getting increasingly unpleasant for everyone involved.

I’m not doing this on purpose. I liked the way I looked when I was heavier (and so did my boyfriend), and more importantly, I liked the way I felt. I *want* to be hungry, I *want* to enjoy eating. Everything just smells and tastes like unseasoned mashed potatoes, and trying to address this issue is just piling more stress onto the situation and making it worse.

What the hell do I do? Why is this happening to me, and how do I fix it before I do lasting damage??