IS THIS POSSIBLE.. can this happen?

Im on birth control, have been for prolly 4 months now. ya ive missed days now and then, ive had irregular short and lighter periods for the last few weeks, not even to mention this last month my period came two weeks early!! well anyway..... i guess i jes noticed this today but ive been SMELLING EVERYTHIN for weeks!! i have been makin comments like everyday saying I SMELL NOODLES ! or I SMELL A CAKE!! or I SMELL BACON!! or CIG!! or RUBBER BURNING miles from a wreck. i guess i never noticed today til i came home and could smell a cake in the oven. lol. well not even to mention ive been SOOO exhausted. ill get out of school at 11am and STILL be SOO exhausted. for the last few weeks its been hard to keep my eyes open, people have even made the comment i look like i just woke up,AND i get plenty of sleep at night but i guess thats just not enough. I started throwing up tuesday night but im hoping that was a virus, and ive been emotional.. and just got off my period(light and short) last week. How freakin' possible is it to be pregnant AND on birth control AND having periods?? I have a 2 yr old already and me and her dad didnt even have and i got pregnant with her! so i kno anythings possible but what are the chances? what does it sound like to you?