Pregnant or just some kind of weird sickness?

Okay, so here is the run down with what has been going on with me. I've been really sick lately. I have awful allergies and got a bad upper respiratory infection and got put on an antibiotic. I take birth control and know antibiotics can make it less effective. Since being off the antibiotics I had to go see my doctor again at school (no insurance) for my post nasal drip. I was prescribed Singulair and Veramyst to help with that to take along with Zyrtec. On top of that I have ADD and severe panic attacks so I take Adderall and Xanax. I also have very bad back problems and had been taking lortab 7.5 but have been off of them for a while. I take Aleve to help with the back pain. My back is so bad that I have had to have 3 spinal epidural steroid injections in the past month or so, every 2 weeks. I have just been going through a lot with my health lately. So for a little over a week about once a day I will get sick and throw up. Even if there is nothing in my stomach except water I will throw that up and dry heeve. Bile is another thing that has been coming up. I didn't know if it could be that I got pregnant from my birth control being less effective due to my antibiotic or just that I have been having so much drainage that it makes me sick. Please if someone has any inkling as to what is going on with me let me know! My insurance is inactive and my school health services provider is not very good. They just want you in and out of there...thank you!!!