HELP!

I'm on birth control (Jolessa or Seasonelle, as it's also known) and I take it regularly as I am definitely not trying to get pregnant (I am a 19-year old college student). I let my boyfriend finish inside of me this weekend and I'm really worried that maybe that was a bad idea. I've been feeling nauseous but I feel like that might be because of the fact that I've been very stressed out recently.
​We did have sex on a "fertile" day but signs show that I never started ovulating (my Basal Body Temp. hasn't increased at all and my CM is thick and white, creamy and kind of sticky.) I feel like it's too late to use Plan B (and I don't have access to a way of getting right now anyway). Could I possibly be pregnant?