Def Cut.... no way the post nasal or even the bump should cause any stomach discomformant (unless its cut which most Coke is.......you can still have bomb coke thats cut, even if its cut like 1% depending on what it is. Baking soda if your lucky but still that old saying.... one bad apple ruins the whole barrel or pie or w/e you get it......) i have had pure shit as in still rock form have to break up from another country. You buzz hardcore and the come down isnt even that bad when its not cut.
just have some benzos for come down or seroquel if your having an issue. I woulod also suggest finding someone new to get shit from.
peace