Im 19 years old. My recent boyfriend and I have had unprotected sex, the last few encounters were over a month ago and we were both inebriated. It's now June 2nd and I last had my period April mid-month. I skipped the month of May. My mother has made suggestions that I could possibly have a thyroid problem. I took a pregnancy test May 27th and it was negative. Could I be pregnant? Could this possibly be a thyroid problem? Or could this be a result of stress? I have been going through many stressful things in my life, I've also gained quite an amount of weight in a short amount of time. I'm also a smoker, my throat has been hurting, and I throw about once everyday. Not a large amount. But Iam still throwing up. Could you give me any idea of what this may be? Maybe give me some suggestions?