Am I stressing or should I be worried

So I had sex for the first time almost a month ago. We did use a condom, I am on birth control, and he also didn’t finish.

I’ve been having back and stomach pain. I called my doctor because it could be a possible uti / kidney infection. He gave me antibiotics and the stomach pain is pretty much gone but I’m still having bad back pain. Should I be worried that I wasn’t protected from sex? It was a video call so obviously he couldn’t examine me since I can’t go in right now. I’m wondering if the back pain could still be from the uti. It’s pretty constant. My doctor and my mom both said that pregnancy most likely isn’t a possibility but I’m still worried about the pain. I mean he didn’t finish so I’m probably over stressing 😬 I think I’ll wait another week or so before I even think about testing