I was supposed to have my nuristerate shot on thursday. can i be pregnant since i had unprotected sex?

Pregnancy unlikely: There is good contraception from the shot, regardless of ejaculations or no ejaculations. As long a a person gets her shots on schedule, she is protected against pregnancy. Getting a shot 2 or 3 days late should not make a difference. That being said, any fertile woman who has sex must be ready to be married, settled down, and raising that cute "surprise baby" that may happen on rare occasions.