Could I be pregnant?

Hey, I'm taking birth control pills, but I still had sex with my boyfriend with a condom (it did not broke and he didn’t put it really deep) in my non-fertile days. (Even so my period ended, I continued to stain with a little brown flow, which I think is one of the consequences of the pills) Well, lately I had flu because of the cold weather here and I was tired and sore because of that, today I vomited only one time (3 weeks later to have sex with him) My period should come in 13 days. Could I be pregnant? It could be only in my mind? Please, help!