Hi im taking rifampin for almost 3months and i need to take oc because i had unprotected sex. which pills will work?

Stop unprotected sex: That means stopping "unprotected" activities, by using other protection. One can consider an IUD or condoms. That can also mean stopping "sex", which can be simply done for 3 months (3 months is a short time). Birth control pills are less reliable (hard to say how much less) while a person takes rifampin, which may decrease the effectiveness of hormonal birth control such as pills, patch, or ring.