15 days late no bfp

Caitlin
My fiancé and I have been trying for about 3 months now to conceive. I'm currently 15 days late. I've taken several tests over the last two weeks and all have been negative, but my cervix is so high i can't even feel it and I've been nauseous. Should I go get a blood test? This would be baby #2 and my first I had trouble getting a bfp as well.