I'm definitely no constipation expert, but I think that taking the Levbid could be making your C issues worse. It's an antispasmodic, so will slow down your stomach contractions and, one would figure, decrease your bowel movements. Hormonal fluctuations can make everyone's life a living you-know-what and can greatly affect your bowels, so this could be another contributing factor. I always noticed that my diarrhea lessens somewhat during my period, which is usually a very welcome relief, although I don't like the heavy/bloated feeling associated with it!
Hopefully this is just a temporary thing for you; I'd second Canyon's idea about increasing your fluids (don't go crazy or anything, or you'll be up all night peeing!), watch your salt intake (too much can increase water retention and make you feel more bloated), take a few daily walks to get things going, and get out a good book to take your mind off it (the latter is how I deal when I'm just an absolute mess - I always keep a stack handy!).
Let us know how everything turns out.
Co-moderator - IBS Forum