Topamax and new doctor

I've been on Topamax for over a year for hormonal migraines, and it's working great for the headaches. I started out at 25mg twice a day and now I'm up to 100mg twice a day. I've lost 40lb (mostly due to the drug -- but my appetite is starting to come back) and have just recently started experiencing the anxiety and tingling in the extremities. I've always felt I've had trouble concentrating and "finding the word", but I attributed it to lack of sleep because I have two small children. My most recent side effect, however, is most worrisome, which is the reason for my visit to this website. I am experiencing severe abdominal pain, almost constant, and it seems to be increasing. I had abdominal pain and diarrhea when I first started Topamax last year, but it stopped after the first month or so. I'm just wondering if maybe long term use can cause ulcers or other stomach problems. Anyone have any experience with this? I know from experience that Topamax dosages have to gradually weaned up and down, so I'm considering decreasing my dosage to see if my stomach problems will stop. I'm just in so much pain, yet my migraines have almost stopped now with 200mg a day, that I'm reluctant to change my dose.