3 days after unprotected sex , boyfriend cumed in me now i have discharge, could it be his seamen? could this still make me pregnant??

Not semen: May benefit from evaluation by your GYN or PCP

Discharge: 3 days after is not semen. It is about the right time for a bacterial infection--from pH issue, overgrowth, or STI--should get checked if persists or odor or discomfort. Pregnancy possible if ejaculation within 3 days of ovulation (=mid-cycle). Condoms prevent these concerns and are recommended unless specifically trying to conceive--prevents complications. Get checked if worried.