I am confused

Okay so I just got over my period less than 3 days ago and I have been having sex with the guy I like for two months now. Last night I threw up at like 2 am and I rarely ever throw up. I didn't really think anything of it I thought it was the chicken riggies I ate but my family ate them too with no problem. Could I be pregnant I had just gotten my period less than 4 days ago? 
(I've been on birth control for 4 years)