Help!!

I am going crazy. I called my doc because I was having extreme fatigue and then a few days later nausea to the point of dry heaving. The nausea typically occurs in the morning and late afternoon. Plus I had spotting a week before my normal period. But no period. I even got off birth control around my normal period time and no bleeding. My doc said this could mean I’m pregnant but I have been getting negative pregnancy tests. I have been pregnant before and was getting negative pregnancy tests at 6 weeks! It ended in a miscarriage but I had enough HCG in my blood to be picked up by a pregnancy test. Has this happened to any of you!? I’m going crazy!