I threw up and felt faint and sweating hard after sex why?

Need more info : There are a wide range of activities under the category of sex. Were your activities very vigorous or prolonged? Was there risk of injury or danger? Is this a recurring, or just a one-time, problem? You may have an underlying illness, an infection for example, responsible for your symptoms. If they don't resolve in a few hours, you should get a clinical checkup. Hope that helps.

Multiple factors:: stress, tension, anxiety, painful sexual intercourse, emotions or simply bad indigestion. Take it very slowly and tell your partner to spend 15-20 minutes on extended ,pleasurable foreplay: you will never vomit from that and quite safe!

Vagal reaction: You are probably a very young person with little experience with this type of activity. Since you have not shared anything about yourself, not even your age let alone any medical conditions, we cannot not provide you with a proper response. Please speak to your parents or consult your doctor and in the mean time, refrain from further sexual activity.