Opinions...anyone experienced this?

Aidan
My husband and I have been trying to conceive for little over a year now. I had 2 early miscarriages late last year. And then nothing until late May. About 2 weeks after ovulation, I started to feel symptomatic. Every pregnancy I have had, I get the nausea and fatigue before I miss a period. Same with this time.
Then I started what I thought might be a period, although it was significantly lighter than any that I've had before and I had no bad cramps like I normally do. I didn't think much of it until 3 days after my period when my symptoms started getting worse. I've been on a steady diet of saltines, Gatorade, sprite and peppermint. Anytime I eat, I regret it. Most of the time I have no appetite. 
I took a hpt last Thursday, 6 days after I had started. It came back with a faint positive. My dr did a blood test that day results back Friday and it was negative. I am still having the same symptoms, plus I'm super emotional and just physically exhausted. People keep asking if I'm pregnant since I have all the signs. 
I have heard some women have negative blood tests early on. Has this happened to you?