It could be stress/anxiety to be honest, especially since you do not have problems on the weekends. I would try stress reducing activities like stretching or exercising, warm showers and getting to bed at a decent hour.
Also, I would not recommend anyone that has any type of J-pouch/ostomy to drink; we have a very delicate system and its good to not put those kind of things in our bodies. I think we should only put holy things in our bodies given everything we have been through and along with the missing organs we have. I hope you give it some thought about quitting alcohol.