Stop drinking if you have an intolerance. When you throw up, it harms your throat. I would just suggest that you tell the that you have an intolerance to alcohol, that way you can be the designated driver.
Also, if you aren't drunk, you won't ever have to wonder what stupid and foolish thing you did with guys while you were drunk. When you're drunk, and passed out, you are subjecting yourself to someone taking advantage of you sexually and may or may not have any recollection of it. It is always good to be in control of yourself,. To be out of control can be very dangerous for you.