3rd day of missed period, had tubal 4 yrs ago, scared to death what should I do?

I'm on my 3rd day of a missed period. I took a home pregnancy test real early this morning ( i couldn't sleep), around 3 am and it was negative. Its 6 am and still no period. I had a tubal in 2008 after my 3rd child was born. I'm seriously worried of an ectopic pregnancy, but I've got no signs of either pregnancy or ectopic pregnancy. I'm not sure what to do next. Should I wait a week and take another hpt, or should I go to the clinic and get a blood test done today? Now I shouldn't be off in my days. I've marked each of my period start days on my calendar, and each period was exactly 28 days apart. :/