5 month old and pregnant

Krystal
I just found out yesterday that I'm pregnant.  A urine test was negative, but my blood test was positive, twice.  My numbers showed I was only about a week pregnant.  I'm wondering how I can find out if that's actually true--I've only had one period since I've gave birth 5 months ago.  Start of that period was Feb 26.  If I went by start date of last period, I'd be 6 weeks?!  Anyone have any insight?!