Have you gone to a Gastroenterologist? If you've been taking it for this long, I think it's better you go. There could be a myriad of issues causing your heartburn, and given that the drug is NOT intended for OTC use past 14 days, I think it's best you get checked up.
H. Pylori is a definite possibility, but it's not the only thing. There are a LOT of conditions which could be causing your heartburn, so it's in your best interest to get yourself tested for these things.
If I were you I would have yourself tested for H-Pylori