I have this same problem, it's a vicious cycle because feeling bad = not hungry = don't eat = eating becomes a big deal = feeling worse = throwing up = eating seems even more stressful = avoid eating = feeling worse...you know the deal. What helped me was to think of things I can stomach and just make sure you're stocked up on it. Chocolate is something that's really easy for me to eat so I make sure I have a lot of it around. I try and give myself a schedule for eating meals and a deadline: if I've not eaten it in an hour, it gets thrown out. Otherwise I'm forcing myself to eat cold nasty food when I don't want to and that strengthens the association of food with nasty stuff. I live in a student budget and when I just couldn't stomach any more cheap food I just told myself my health comes first and went to the shop and bought anything that took my fancy. I stopped worrying about eating 'proper meals' or feeling bad if I didn't manage to eat a lot and that helped a lot with the stress that was killing my appetite. I also try to have eaten 3 meals by 6pm so I can have the rest of the evening to de-stress or snack on bonus calories.

I too got hooked on meal replacement drinks but I figured out they actually make my tummy even more uncomfortable, so I'll only have them in an emergency before bed once I've at least attempted to eat three solid food meals - if I have them in the morning I don't want to eat actual food.

Another weird tip which I'm not exactly sure is healthy...you know when you're learning to ice skate and you can't get better until you've fallen down once? Because before that you were too scared to get any momentum up because you were worried falling would be horrible? Well, when I think food is absolutely disgusting but I know I need to eat, I just shove it down me anyway. If it makes me throw up, I find that immediately after I'm able to eat without a problem. Must be the endorphins released or something.

I hope you'll get over this soon, it really is a horrible problem to have. It will get easier - the less you eat the more your metabolism slows down and the less you want to eat. Once you start eating little and often your appetite will probably start to return.