What makes you think your girlfriend has HIV? Also, women don't produce semen, only men do.
She's your girlfriend. Is she HIV positive? The only ways that people get HIV is from unprotected vaginal or anal sex or sharing of IV drug needles. Saliva has enzymes in it that inactivate the virus and air inactivates it. So, giving oral to your girlfriend (who again, is she even HIV positive? This isn't some unknown person if she is your girlfriend) would not put you at risk in any way for HIV. So, no risk.
You can't get HIv from oral so you are safe and don't have HIV. Probably your shaking and twitching are just in your imagination from fear.