hey H.,
you might have IBS, you might have something else. there are a few things i would try to rule out before you jump onto the IBS bandwagon. docs are so quick to prescribe drugs than to get to the root of many problems!
this will sound gross, but stick with me for a sec. if your diarrhea is watery, that might mean one thing, if it is like soft serve ice cream that's entirely a different story.
watery diarrhea would point in the direction of a bug of some sort or inflammatory bowel disease - which is totally different from IBS. IBS is related to psychological stress and varying hormone levels in your body, and IBD is a reaction of your immune system. you might have heard of crohn's disease... something like that. IBD will have to be diagnosed by your doctor.
if it's soft serve ice cream, it could also be IBD, or it might be a nutritional thing. that's going to require you to do some experimenting with your diet. two obvious things that people often over look is an allergy to gluten (wheat) and not being able to digest lactose (lactose intolerance). these are very common, yet go years without discovery because wheat and dairy are staples in the american diet! i found out i was lactose intolerant after 4 visits to 3 doctors only for them to tell me they couldn't find anything, so i decided to check it out myself. i cut out ALL dairy for a week - and lo and behold i was back to 'normal' (this was after YEARS of funkyness) within a couple days. it was amazing. try that first. it's the easiest one to do. if that does not help it, then try to cut out wheat/gluten. hard to do, but normal poop to me is worth it! there are online recipes and guidelines for what you can and can't eat.
you can also search online for other dietary problems other than those that pertain to specific foods/ingredients... but those are the two that are a)most common and b)easiest to self-identify.
IF one of these things work, then you will not have to take any medication, and it will never be risky for you to conceive. you would certianly have to monitor your nutritional intake, but that would be it.
IF none of them work (neither dietary or IBD), then i would consider making an appointment with a psychiatrist. IBS is actually a psychiatric thing more than a body thing. sounds crazy, but it's true. soooo many people have it and don't get the proper help for it. many gastroenterologists will end up referring you anyway. they should, at least. if they don't - find another one :).
good luck with all of this. bowels are never fun unless they are working top-notch.
C.
pax