i'm feeling nauseous!

hey girls! let me explain what i'm feeling so me & my bf had sex the day i left for my trip i had a week left of my birth control that same week i had my period i finished my period & ended my pills that week it was the last week of july ,today just a few mins ago i went to my kitchen smelled shrimp out of nowhere it was a strong smell i felt really nauseous i simply ignored it did my bowl of cereal after i ate it i still feel nauseous like i just want to throw up my cereal. my question is, is it possible to be pregnant?

i really don't know how birth control works since i started taking it last year after i had my baby just a few months after, also i've been getting mild cramps life if it was my period but nothing happens i was supposed to get my period this past monday but nothing has happened.