I had sex with a girl who had one night stands and now I'm having a small rash on my body

Hi Everyone,

I have been worrying for the last few days and plan on seeing a doctor but wanted other peoples opinions due to my concern.

Nearly 2 weeks ago i slept with a girl, before we began i asked her about her sexual history and she did say she had one night stands before and a few months back she was worried so got tested and was negative for everything. She said between that time and me she had sex with one guy who was a virgin and it was protected, orally i assume it wasnt.

When me and her had intercourse it was with protection but orally it wasn't, i have no cuts within my mouth area however.

Recently i developed a cold, my friend did have one but is a dry cough which gets quite intense, sore throat, runny nose. I did feel hot the other night but very briefly and am fine in that respect. When getting dressed however i noticed on my back i had a small rash but i cant tell if it is bites or in fact a rash, it isn't all over my body or wide spread but rather just a small area and it doesn't hurt or itch at all.

I have spoken to her and others and they think its likely just a common cold it is just the rash that worries me as i never had one like this, maybe its unrelated?

I plan on speaking to a doctor and she has told me the girl i was with that i will be fine but the worst case keeps playing in my head and i dont want HIV especially when i used a condom.

Wondered if people could give their advice and opinions.

Thanks