Im scared if i pregnant?

I just got off my period 3 days ago, Im on Lutera birth control and i usually start my period as soon as I start my pink pills but i didnt start till I took the 3rd one this time, resulting in a 4 to 5 day period. I had sex on the fourth day of my period and ive been told that the hormones from the birth control stay in your blood during the time that you arent taking the active pills. So here I am 3 days after my period and for the past 2 nights ive had a very upset stomach at night and ended up throwing up. I dont know if this is just me being sick or something else. This would have never even crossed my mind had my mom not just mentioned it. I have minor cramps currently but I think that might just be a sign of me overreacting. Im sure this question has been asked, ive looked all over for it but none of the ones ive seen showed that they were currently on birth control. Ive been on Lutera for 9 months. I really dont want to just go out and get a test for something that im just paraniod about.