I track my periods, symptoms etc since many months back using a phone app. I have noticed something that I'm curious about. Almost every cycle ends with a bad stomach day/diarreah. On day 5-7, almost every month, I've had diarreah. Today is really annoying with bad stomach, back ache, a cold and itchy boobs. Can I be reacting to rising estrogen levels at the end of my period? Or rather over-reacting since I'm peri.....I obviously can't be affected by a virus every single month on the same day!