Topamax and old lady

I am a 62 yr old lady that was started on Topamax a little more than 2 yrs ago for migraines that were getting worse as I was aging. After the first "weaning on" period I have been taking 100mg a day at bedtime for the entire time. Initially, I had a lot of tingling in my hands and feet, but it subsided somewhat and never seemed like a big deal. The Topamax brought my migraines to a grinding halt. However, more recently I've noticed quite a number of new increasing symptoms that are bothersome and scary. Difficulty concentrating, a certain amount of confusion, and some eye pain that sometimes feels like pressure and my vision is blurry. My balance does not seem quite normal. I'm not really dizzy, but I have "missed" a step too many times lately. My mind functions do not seem all together "there". Normal functions like spelling, counting change, answering questions, like my address and phone number, aren't always easy especially if I'm under pressure or get upset. Backaches and joint pains are present, but since I have Degenerative Disc Disease it is hard to distinguish the source of the pain. The problem is I cannot determine if this is from the medication or if I am experiencing another kind problem. ? Most medications have side effects; however, if the benefits out weigh the (negative) side effects, it is worth it.