It's the same class of drug as cipro, although it's a bit more broad spectrum. I used levaquin and cipro for PA for a long time, and they helped until I eventually had to quit taking it due to tendon troubles (a listed but unusual side effect, I think).
If you have taken a lot of cipro, that may be your problem. Otherwise, I would definitely think it should have worked by now if it's going to do the trick.
Hope you're feeling better soon!