Some of the SSRIs can cause GERD, and Prozac is one of those listed that can. When I took it, I had increased stomach acid but not extremely severe. I just googled "prozac" and "GERD" and found results where people were claiming that some of the generic prozacs cause problems and others don't.

When I took Prozac, I lost weight on it at first but after a couple of years, I started to gain slightly. This was a long time ago, too, when I exercised regularly and was very thin.

If you see a primary care doctor, I would make an appt. with him/her to ask about it.