5 weeks late...neg. urine test?

I had my last period in late November. I have not been on birth control steadily for the last year. I had unprotected on the December 2nd and about two weeks later I "thought" I got my period, but it was really only light spotting that of course I thought nothing of at the time. 2 weeks ago I fainted at the mall and that is when I started to put everything together. For the past few weeks I have been sick to my stomach, vomiting, my are sore, as well as frequent back and headaches. I only realized that my period was late after I fainted. I dont keep track of when my periods are due because they are ALWAYS regular. I have taken 3 tests all neg. I just lost my health insurance so I dont want to run to the doctor for a blood test if I am being crazy. Has anyone else every had neg tests but actually been preg? I figure if I am pregnant I should be about 9 weeks. My boyfriend thinks I can't be because I should already have a positive urine test. Thank you for any imput you have.