Is my Truvada working?

I heard there's common side effects but I'm day 6 on the medicine, and I've not felt a single side effect (call me lucky I guess, maybe?) but I'm afraid it's not doing anything? Now I don't have HIV from what I know, but I believe I may have come into contact with it, so they prescribed me this for PEP (Post Exposure). I'm wondering if this is okay?