Pregnancy Test Negative???

[Campbero]

I am 31 years old, plus size women 280lbs.   My spouse and I have been trying to get pregnant.  Been unprotected sex since end of September 2016.  My last period was October 2nd -6th 2016.  On November 11th, I had a one time light pink spotting.  I have not had a period since October.  I've taken 3 test in a week time all negative.  I feel nauseous on and off, Dizziness out of the blue, bloated, heartburn, smells that turn my stomach.  Constantly have headache,  tender boobs, lack of sex drive, existed all the time.  Any thoughts??