Here's a lot of detail:
On July 15th I had unprotected sex. I was due for my period on the July 17th. I didn't get my period until July 22. After I had unprotected sex, on the 17th I started to get itchy down there. I figured I'd let it go for now thinking it would clear up. It eased up a lot after I had my period, but its still a bit itchy to this day (august 11th). On August 6th I started to get a real sharp pain in my lower side, which later that day stopped and then I had really bad cramps for a while. Since the 6th until today I've had a bunch of random pains in my stomach area. (nausea, sharp pains under my ribs and my sternum and some back pains). I went to the doctor today and I didn't mention the itching to him, just the stomach pains. He said it may be like pre menstruel cramps and that if they persist for a few weeks he'd run more tests.

My questions are
If I wait a few more week, and I actually do either have and STI or ectopic pregnancy will it hurt me or will it still possibly be treatable?
If I had my period, is it even possible to have an ectopic pregnancy?
What do you think may be wrong with me?
And can I ask a family doctor about being itchy down there or is that specifically for gynos?

so sorry this is long, but I figured the more information I gave the more someone would be able to help me. And I've just been extremely worried lately about PID cause if I found out it damaged me and I can't have kids I'm going to feel like crap cause I want kids so bad.

You consulted with a Physician who examined you and knows all of the circumstances.

I would believe him/her over advice you receive here. Perhaps you need to call him/her again and express your concerns.

If you want to make sure you're safe, protect yourself - against both pregnancy and disease.

You should go back to the doctor and mention the itching since you didn't before and get a test done for stds