Could it be dairy consumption? You mentioned you didnt see a direct link when you ate the SA & then the cramping. I used to be a real dairy hound- all my life, with no problems, then when I was aabout 32 or so BAM! I started having the same issues you describe- cramping, running to the restroom etc. After a couple of weeks I finally tried taking the Lactaid pill before eating ANY dairy- it was an experiment- but it worked! Turns out you can become lactose intollerant anytime- usually as you get older if its going to happen. Maybe this is part of what causes your sickness? it might be worth a try to get a small pack of these pills, or give up all dairy for a week & experiment. Usually my symptoms start between 45 min. -2 hours after i eat dairy (if i dont take the pill first) Too many S/As bother my stomach also- but since its usually bars or chocolate (that have dairy in them) I attribute it to that most of the time.
Good luck!