Really scared, please help?

My husband and I have been ttc after a very painful miscarriage at 11 weeks(we only started trying after we were given the go ahead from my doctor). Well after some hesitation we finally got excited to try again and today I am one day late for my period. I took a hpt and got a very faint positive line(I didn't take it with my first morning pee). Now I am so very very scared. I called my doctor but of course they are closed for the holiday and won't be in until monday. What should I do this time around? Is it unreasonable of me to request early ultrasounds so that I don't get too excited? I want to embrace this time around with excitement and anticipation but I can not shake my terrified feeling that we will again lose our beautiful baby. Any advice or kind words is greatly appreciated, thank you-and I hope everyone had a nice thanksgiving!