I just had an unprotected sex with a stranger girl and now i fear that she maybe an hiv patient is there a way to protect myself from being infected?

HIV prevention: In the US, even among the most sexually active women, the chance of HIV is low, usually under 1 chance in a thousand. If she is at special risk (e.g. injection drug user, commercial sex work) and the event was less than 3 days ago, see a doctor to discuss post-exposure prophylaxis (PEP) with anti-HIV drugs. Or contact your partner and ask her to be tested; if HIV negative, you're home free.