no period after miscarriage - please share experience

I had a very early miscarriage (5 weeks) on November 28th. Using that as my last period, my period is one week late today. I've taken several pregnancy tests and they've all been very negative. If my period doesn't come sometime this week and I don't get a positive test, I'm going to call the doctor next week. Have any other women had similar experiences and when did your period come? Thanks in advance!