what's going on? late but BFN

I've never posted here but I'm trying to figure out what's going on with me. 
Some background- been TTC #3 for six months
Tracked periods over the last year, cycles alternating from 28 days and 32 days
I'm currently on cycle day 42. 
So in November we baby danced at O. I started my period Dec 4th, nothing out of the norm except it was 3 days instead of 4. No period since, no sex since. Which means if I am pregnant I'd have to be 9 weeks. 
I've taken two tests, both negative but I have some symptoms. 
My question- has anyone had something like this happen and you were pregnant?
I've read on the web that it's possible and read plenty of stories of it occurring but I just can't imagine a hpt not showing it. 
Having one "period" is normal, happened with my son but no BFP..... idk.