HCG Levels

I am 5 weeks pregnant and o went to get my HCG levels tested and the first number was 775 then in 48 hrs it was only 885. I was told that number is suppose to double? Anybody have this experience and please tell me something good came out of it? I have to wait until next Thursday for my Drs appointment and I am trying not to loose my mind but it's really scaring me. This is my first baby and I couldn't want it more!