I'm being stress of not having my period! I'm so worried. 😳😳😳 I'm bothered. I need help

last month january 6 i had a contact with my bf and he cum inside me. but before that i took pills at that same date. supposed to be my period should be on the 26th day of january and ends on the 2nd day of February but it didnt came. I continously took the pill except for the brown pill or the iron pill. I immediately took another pack of pills.I didn't know that those brown pill could help from getting your period i think?(thats what my friend told me)... I took pregnancy test four times. And it was all negative. .. I just want to ask .Is there a possibility to get pregnant? .. I'll take the last pill(active pill) of my second pack tomorrow. and the next day im gonna take the brown pill hoping to get back my period.