Hi, ive had sex with a guys today (im male too), when we were doing it he inserted his penis into my ass unprotected (i didnt know he was gonna do it before wearing a condom) but i freaked out (cos i wanted to use a condom) and removed it straight away (only his tip got in). i had asked him before hand his std status (he said he was negative) and i asked him after too and he again said he was negative.but im afraid, should i be?, the contact was for lass than 5 secs, what should i do?