What could be causing my pelvic pain? What are the next steps/tests needed to get to the bottom of it?

I've been experiencing pelvic pain for nearly 3 months now. It started as what I thought was a standard UTI and was treated for such. The pain persisted so I was then treated for a bacterial infection. That was before the holidays. I keep waiting for the symptoms to subside with no luck. I've never had anything really like this, so I'm starting to worry. The main symptom is pelvic/lower abdominal pain. It sometimes radiates to my lower back. I also get nauseous. I feel a pressure where the pain is, and it sometimes feels like it's pressing on my bladder or bowels especially upon waking in the mornings. There also appears to be some discharge sometimes and rarely somewhat painful urination. Minor changes in menstruation as well. I've had a cough that has waxed an waned for about the same amount of time. I don't imagine it's related but figured I'd throw it in there just in case. I've reached out to my doctor who's not gotten back to me yet. As I mentioned, I've never really had symptoms like this, so I'm looking for advice on what the next best steps might be to get to the bottom of it. Please advise. Thank you!