I fully understand where you are coming from. I suffer from IBS (thanks to PCOS) on and off (haven't had it much since being on metformin) and I did still get it during pregnancy. I would suggest talking to your Dr and asking about a pregnancy safe metemucil type supplement. I had one when I was pg and it definitely helped. The constipation and back up causes the rest of the stool to go soft, irritate the bowels and causes the diarrhoea. It is EXTREMELY painful and there are times where I've nearly fainted from the pain. There is a product called "digest ezy" which is my best friend LOL but you'll need to find out if its safe during pregnancy.

Goodluck, but definitely talk to your Dr.

*hugs*
Cailin