Change of behavior

I'm on a new drug called Neurontin, and it is changing my personality. I'm actually friendly now, and it bothers me. How can a pill change my personality? It prevents seizures and takes away the constant pain I used to be in, so I guess that's good. But I was friendly before and it led to me getting hurt and pushed around. I think I liked being a jerk. But I don't know what to do. Oh well, guess I'll run with it. Better than being in pain.