Advise???

I'm six days late. I took a test earlier today and it was negative. I have very regular cycles. If anything they are a few days early. Stress has never affected my period. So I don't understand why I'm this late and getting negative tests. But right now I'm dizzy. So dizzy I can't really stand up. I have been drinking as much water as I can and eating when I can. But this just started happening about an hour ago. I don't understand why?? Any advise or idea of what's going on?? I am also TTC. I know you're not supposed to try to find pregnancy symptoms but I'm really nervous and worried something is wrong