Had unprotected sex during periods. took emergency pill post 70 hours of intercourse. after 4 days there is some brown thick discharge. m i pregnant?

Likely, no: If you had unprotected sex during your period, the chances of pregnancy are low but not zero. Your discharge now doesn't say a lot about whether or not you are pregnant. 70 hours is a little late, maybe consider having some on hand in case you need again? Or a more reliable birth control method like pills? If you miss your next period, take a home pregnancy test. Good luck!