AF hasn't shown up since October 14!!! Confused!

I've taken numerous hpts and have gotten nothing but BFN! I went to the clinic today, and they took a tribe test and of course, it came back negative also! I'm so confused with what's going on!? I'm not sure if I should go back and request a blood test to put my mind to rest! I have some pregnancy symptoms. But I don't want to make my mind trick my body to think I'm pregnant if I'm not. I've read several pages of women who do not produce enough hcg to get a possitive in urine test. Just so confused. Any advice?