You're on 20mg of Xanax? Wow, call a friend over if you feel the coke wearing off and the Xanax taking over your breathing capabilities, as you might not feel the full effect of downers while on stims, leading you to take more and more xanax/heroin since you don't feel it while coked out, then when the coke wears off, whoops, possible overdose.
I hope your benzo tolerance is high with a whole 20mg of Xanax...