I had a similar problem when suffering from severe anxiety and depression last summer. I didn't get skinny to the point it was concerning, but would have if things hand't changed.

What changed? I started dealing a little better with my anxiety, mostly due to confronting the person whose behaviors caused my issues to begin with. I've also started meditating and started talking it out (in PMs) with a couple of people from this site who understood my pain.

For me it also helps to take Rantidine twice a day. It helps with the stomach acid which helps some with the vomiting. I take it in times of stress and have been dependent on it to keep my food down for the past 9 months or so. I still have pukisodes even on it from time to time, but much less. I also started drinking instant breakfast drinks to keep me going, just a couple sips at a time and a couple of drinks a day until things improved and I was able to keep that down until things got better and now i can usually keep small meals down.

I want to advise you to see a doctor, but I'd be a total hypocrite as the first time I had issues with the vomiting it took me 3 years to talk to a doc about it. There may be a medical cause that can be treated. Mine was acid reflux triggered by stress.