Day 51, negative blood test


I'm on day 51 of my cycle and I'm normally on a 35 day cycle. I had one faint positive urine test, 4 negative urine tests and 1 negative blood test.

I have swollen breasts, super hungry and tired, smell aversions, and nausea. The OB wants me to take a pill to make me start but I'm scared the tests are wrong and I'm really pregnant...what should I do?