Have you consulted any other doctors? I really don't think being on penicillin for a long time is good, what are you taking them for?
You know how they are all worried about bacteria becoming immune to Antibiotics and penicillin? I think that you taking penicillin all the time is going to causie this immunity of some sicknesses for you, and its definitly not going to help your bodies own immune system. It may become dependent on it. I may be repeating myself.