Ive recently had a couple episodes happen to me where it starts out as sudden severe nausea then so hot im covered in sweat. then i feel like im. going to faint then im freezing all in a matter of about 3-4 minute. what could it be. very scary ?

Scary Episodes: I would wholeheartedly agree that the episodic symptoms you've described should have you concerned. There are a myriad of factors that may be causing this, but without a complete medical history, an examination, and possible blood work it would be irresponsible to guess what ails you. Please see a local physician for an appointment, a proper diagnosis, and treatment options.