Try not to get too discouraged. Antibiotics cause me a ton of problems too. Take the probiotics and eat yogurt, as everyone has suggested. But I think antibiotics are very destructive to our GI tracts. They are treated like they are no big deal......but I think they can really cause us alot of problems.
Are they figuring out why you're getting so many UTIs? Try drinking unsweetened cranberry juice regularly, and you may get fewer infections. And always wipe from front to back and wear cotton underpants.
Please don't think you will feel this bad forever. It will get better. You just have to figure out how to get there from here. :)