DIAREHHA!!!
Eliza,
I was having this problem for about 3 weeks, and my NPA gave me some VALUABLE advice.
Immodium tries to pull all the water out, so that you do bulk up evenutally. That stuff doesn't really work on me anymore since surgery.
Kaopectate serves as a bulking agent, which worked VERY quickly for me. Just becareful not to take this long, or you'll go from one extreme to the other! Best of luck to you!