Maybe Pregnant?!

Beth
My period isn't due until tomorrow, but this week I just had a feeling and took a pregnancy test. It was a faint positive but definitely a positive. My husband and I have been trying so I was very excited! I took a few more tests just to be sure- they were all positive. I went to a Dr.'s Care to confirm the pregnancy, but the urine test they gave me came back negative. I showed the Dr pictures of the pregnancy tests I took at him and she said they definitely looked positive so she ordered a blood test. They took my blood and said I should hear back the next day (which was yesterday). I never heard back so I went to the office today and had to ask for the results. The receptionist just printed off a paper and handed it to me but I had no idea how to read the results, so I had to ask to speak with someone who could. She called a nurse or nurses assistant over and handed her the paper and the lady proceeded to tell me that my HcG levels are very low so maybe I miscarried. I was shocked and instantly heartbroken. I then asked her well I'm only 3-4 weeks, is it possible that is the reason my levels are so low? And she said "yeah maybe that's it. Anymore questions?" I just said no and left. The paper she printed me has my name and info and all on it, but it doesn't say anywhere on the paper what my HcG level actually was. I came home and took a pregnancy test and it turned positive within a minute. 
Is it possible for the blood test to be negative with me being so early? I've been taking at home urine tests and they turn positive faster each day. I called and made an appointment with an OB but it's not until June 5th. Has anyone had anything like this happen to them before?! I feel so sure I'm pregnant! Any insight on the issue will help! Thank you!