I have only one question: Is a friend who encourages you to engage in behavior that is potentially damaging to your well-being in any way (physical, emotional, or psychological) *really* a friend at all?

No offense MMF, but this "friend" of yours sounds an awful lot like a lot of the "friends" i had years ago who would beg me to go clubbing with them even though they knew I had a drinking problem and was trying to quit. This woman was *very* aware of your vulnerability and she took advantage of that. Obviously, you played an integral role in what happened once her offer was made, but I would urge you to think about why you would want to maintain a friendship with someone who clearly did not have your best interests at heart.