I don't think throwing up after drinking is caused by drinking too much alcohol than the body can hold but rather inability to conduct oneself properly after drinking alcohol. It happened to me a couple of times, and I believe I could control that simply by conducting myself properly afterwards. Conducting of oneself is however, subjective. What works for you may not work for another. Generally, I think going straight to bed immediately after drinking is not a good idea.
I don't know of any allergies to alcohol tho.