I'm 21 years old and have never had health problems until now. I've been very sick-vomiting, light-headedness since mid-July. My menstral cycle is never regular- sometimes 3-week cycles, sometimes 5. It has been 7 weeks since my last period. My last one ended on July 20th and on July 21st, my boyfriend and I had sex (we used a condom)--and have not had sex since. The symptoms (along with weight loss) continued so I went to the doctor around August 1st. I had blood work done and all he said was that I had an infection and prescribed antibiotics. I'm still not better and have not yet had a period since.

I am visiting the doctor again this week because the sickness has only gotten worse, but do you think even with having "protected" sex only once the day after my period and having blood work done at the doctor that I could still be pregnant? The only pregnancy symptoms I'm experiencing is a late period, vomiting. No swollen breasts, no frequent urination, no cramps/abdomen pain, etc. My grandma, grandpa, mother and sister all have thyroid problems--would this cause vomiting and a missed period? I'm just a little nervous before I go back to the doctor and I guess looking for some reassurance--I wasn't exactly planning to step into motherhood already...

Thanks.