AF was due 2/14. Neg tests help

I am 38. My husband and I have tried for 2 years to have a baby. (Halfheartedly anyways.) recently his sex drive has had a boost. We had intercourse most days during my "fertile" days. The only time my period has ever been late was when I was pregnant for my son 13 years ago. I've taken test after test and all have been negative. I don't have extra stress in my life right now. I just don't know what's going on. Am I pregnant and just not getting positive tests or is my body just behaving weirdly. My last gyn spot everything was normal and she said there was no reason I should not be able to become pregnant again.