Pregnant or Not?

Patience, something I really need to learn. Yesterday morning I took a pregnancy test. Now first let me say the pregnancy test says to wait 3- 5 minutes for results. Well I waited a good 30 seconds, gave up and threw it away. Well later on I got the feeling I should check it again. Well it showed positive for a baby. YAY, or is it to soon to say YAY. It was one of those early pregnancy test, so when I went to the Dr and took their regular one it showed up negative. So they did a blood test. After I swear the longest day of waiting I finally got a call 3 minutes before closing that said I had a level of 20 hcg. Well less then 5 is not pregnant, more then 25 is pregnant. So what about us in the 6 to 24 range. They said to come back in 3 weeks for a ultra sound to know for sure. Well for now I still haven't started my period. I guess I will just have to re-test in a few days with a regular pregnancy test to know for sure. So wish me luck.