11 pregnancy  tests (all neg)  and still no period.

Okay so here's my story, I am an 18 year old, the last times I had sex was on October 16th, 2007, well A few days later I lost my young cousin (10) to cancer. I was a wreck, a week after her passing I got my period for 8 days. Than I havent' had it since, I took many at home pregnancy test, about 11 all of them came out negitive, and today I went to the doctor for a blood test because I just thought it was stress related, but with me keep worrying about it and thinking I think I am. My stomach has really bad pains, and its hard on the top under neath my boobs, I get clear discharge and I pee every half hour to an hour. I told my mom I was tested, and boy that didnt go down to well. My parents are threating to kick me out because im a senior in high school and start college in the fall.. I took another pregnancy test today with my one friend Alyssa who is 7 months along herself. What should I do?