I have a bump, not completely way in my vagina, but just a little in. And when I sit I can feel it and its sore and irritating. When I touch it, it kind of hurts. I just had sex about 3 weeks ago for the first time, and we didn't use a condom. So what could this be a sign of? An STD, I'm pregnant, herpes, what? Im really scared. :/

Yes it could very well be an STD, having unprotected sex is not a smart move at all.

However it could just be a cut or tear that is healing.

Time to book in for a doctors appointment either way.