Had oral sex with a call girl and she was in her periods but did not know am i at risk for anything?

Risky: It is always risky to have sex of any kind with a prostitute. Get yourself checked.

Very low risk: Sex during menses doesn't raise STD risk. And oral sex in general is safe -- not completely risk free, but far lower STD and HIV risk than vaginal or anal sex. Finally, many (most?) call girls or escorts (expensive sex workers by appointment, not pick-ups or brothel workers) know the score and work hard to stay infection free. If this is your only risk and no symptoms, I see no need for testing.