I wouldn't get stressed, regular health checks, use of condoms during penetration and the low probability of catching it via oral would mean your pretty safe. Though it would be better if you found at that sort of infomation before doing it will save you on a lot of unnecessary stress. As I understand it even having unprotected sex with a girl with Aids dosn't have a high probability of you catching it, other things are far more contagious (just lower consequences if you do catch most of them). Transfer from infected males during unprotected penetration of there partners has a much higher probability though.
Don't take me as an expert though, read something written by a doctor or ask a GP some time.
The transmission formula for working out HIV risk is
Virus Present + Body Fluid + Mode of Transmission + Point of Entry = Risk
So when you work out if you might be at risk of contracting HIV infection you need to go through these factors.
From what youve said - you dont know if the girl has the virus - and girls usually get bloods done every 12 weeks and is illegal to work knowing you have HIV
There were vaginal fluids present - Im assumin you didnt use a dam
There was a mode of transmission - unprotected oral sex
But you also need a point of entry - like any recent dental work, cuts in your mouths - sores etc.
If you cut out any one of these factors - theres no risk.
Consider dams - girls still get off and we use condoms on guys.