An Infection Getting Worse and Worse: Can I Just Wait it Out?

I am 15 and I just had sex for the first time last Friday. It was unprotected but he did not cum. The next morning I had pain. The pain continued through Saturday and Sunday. I thought the pain was from having sex for the first time, but it's now Monday and I realized stinging while I pee, cloudy with some blood in it too, in addition to constantly having to pee and never feeling empty....