Periods, stool, and probiotics

So I’ve recently had and egd and colonoscopy because I was having some stomach issues. They found my esophagus and stomach lining were severely burned from the acid and that I had an intestinal blockage. The doctor told me to take miralax regularly but it made my stomach hurt and caused serious bloating and gas, so I stopped taking it and have been doing fine until lately. I’ve gotten a bit backed up since my period before last because I have extremely painful periods and I cant poop because of the pain when I’m on them. So i went and got a probiotic thinking it would help everything. Ever since I started taking the probiotic, I’ve had a ton of mucus in my stool which made me stop taking it but it’s still going in and now my constipation is worse. The mucus is starting to worry me so I’ll be calling my GI, but has anyone had this happen with probiotics? Also, is it normal for it to be painful to use the bathroom while on my period?