Where the hell is AF?

Abigail
So confused.
37 years old, 3 children...TTC #4
I've had normal missed period and BFP scenarios always. This month I'm a week late, spotted around the time I ovulated, Spotted within a couple of days of when AF should've been here but NO Period! I've taken 3 test all BFN. I peed on that stick anticipating a BFP, I'm bloated, cranky, all kinds of food aversions, I can't even tho K about a cup of coffee!! my nails are rocks hard...all of which are always indicators for
 me aside from sore boobs, I'm not sore.
Is it a waste to go to the dr and ask for a blood test!? I mean why now would it not show up after 3 kids,  1MC & 1 chemical. Baffled!!!