I'm 18 year old Male and recently (2 weeks ago) had sexual experiences with a girl from my college. She told me she was a virgin, but she did other things like oral sex and such. She said she had given oral to 3 guys before and I was the third to give her oral. I did have intercourse with her but I wore a condom.I'm pretty sure that I'm probably fine downstairs but I'm freaking out that maybe I might have picked up something when I gave her oral. I don't usually get any bumps in my mouth but I did wake up this morning with a small bump on the roof of my mouth towards the back. It's slowly going down now but it freaked me out. 

My brothers who have been with way more women think I'm fine but I'm still worried.

I'm going to get tested later today, but I was wondering what are my chances of having an STD?