Can An Ovarian Cyst Cause Vomiting?

I have severe nausea and its led to involuntary vomiting. I've been to the doctor's and they're saying I'm not pregnant, but have an ovarian cyst. I am unable to eat regular foods because for the fear of regurgitating then again. Is it the cyst that's making my nauseated? If not, is it possible I could be pregnant, but w/ regular cycles? I know its not possible, but there are a few rare cases in which it can happen right?