freaking out

Sophi
I've been on the pill 4months, never missed a pill. But last month I tried this vitiamin that supposedly helps with depression, I didn't like it so I stopped after 2 days (this was toward the beginning of December) which was before I started my period on the last pack of pills. 
This month my bf came inside me for the first time,and I just learned that the vitiamins i took can interfere with The pill! Do you think there's a likelyhood that I could be pregnant? (Sorry if this story sounds confusing) I've gotten my normal period symptoms.. but I'm feeling a little paranoid. My period is due in a few days btw.