I had the same thing -- 2,000+ at 15 dpo. I also stressed about the same things. They even did an ultrasound since at 2,000 you are supposed to be able to see a sac (I have a history of ectopic, so was closely monitored). Well, it turned out to be a healthy girl we have in there! (Negative on all the screenings for chromosomal abnormalities). So, hang in there! Most likely, it's nothing, but definitely try to get an early ultrasound to rule out molar pregnancy. It also could be twins, or it could be a girl...I have had many boy pregnancies with "normal" betas, and this girl pregnancy is the only one that I know was a girl and had these high numbers. I have read articles suggesting that ON AVERAGE, hcg is higher with girls than boys (though that is simply on average, and any given number can not tell you whether you have a boy or a girl). Try not to stress!! Mostly likely everything is fine!!