Re: More advice needed - several questions
1. Obviously, any drop in PSA level is good, but PSA is susceptible to short-term swings because it is impacted by lots of variables. It is logical to conclude that this drop is an indication that your antibiotic therapy is working and apparently your doctor thinks so. See where it is at the end of 30 days. Sometimes longer term antibiotics are necessary to treat prostatitis.
2. You can always seek other opinions and should do so if it will make you more comfortable. If you seek another opinion, seek out someone with lots of specialized expertise, often found at a university medical center. Even if you have a biopsy, you are playing a game of statistical odds. A negative biopsy doesn't mean you are free of cancer. For example, when I had a biopsy, 12 samples were taken, 6 from each side of my prostate. The samples are extremely small. Of my 12 samples, only one of the samples showed cancer cells in less than 5% of the sample. However, my post-surgical pathology report revealed that 10% of the prostate was cancerous. It is quite possible that if the twelfth needle had been in a slightly different postion, the cancer would have been missed entirely.
3. All men should be concerned about prostate cancer. With your one incidence of family history, and now with a history of inflammation at best, you should be more attentive than others. That might mean you could have sporadic PSA tests before the normal age when they are recommended and respond expeditiously to any other symptoms you might experience. But remember, based on this experience, that elevated PSA does not necessarily mean cancer. If you get good results now that suggest you don't have cancer, don't become obsessed with the possibility of cancer. Enjoy your prostate while you can. Should you develop cancer in the future, the good news is that there will be even better and more effective treatments available for you than exist today.
4. After surgical removal of the prostate, the recommended time for testing PSA is three months. That would suggest that it takes at least three months for the PSA levels to reflect the changed condition. After surgery, the PSA level is supposed to be a statistical zero. I'm sure your doctor or other sources can give you information about the waiting time for PSA testing after an infection.
5. I think your body will give you the best answer about this. However, most of my reading has suggested that ejaculation plays an important role in treatment of prostatitis because it drains the prostate and assists in clearing the infection. Try a Google search of: prostatitis and ejaculation. However, as you have learned, for best results, avoid ejaculation at least three days before your next PSA test.