I think some people's bodies take longer to make the amount of HCG necessary to make some pregnancy tests turn positive. Your reg doc will usually do a blood test for you if it's easier to get to them than the OB. Good luck to you!
your welcome.
I went to planned parenthood when I got my test, and it was free! and they give you a packet of info, and can help you out with the best OBGYNs in your area.