Getting so worried and stressed?!

I think I'm just about ready to curl up into a ball and cry and sleep!!! 6,days late, completely missed my period, and I'm 4 days away from my next fertile window.... According to my tracker app, done a digital test the other day, and was advised to used the normal ink tests, so used the ones that the GPS test you with....

Still negative! I have no pms signs at all, but I'm super fatigued, I'm constantly needing to go to the toilet, I keep getting weird tingly feelings on my nipples and like a weird feeling in my stomach, almost as if I'm in a rollercoaster and you start feeling that weird sick feeling?

Anyone else had any of this before?