Don't worry about how fast the levels change. They are different for every pregnant woman. Different levels, different change rates. Sounds to me like the baby is doing awesome especially since it was only 2 days and it went up that much. I would just sit back and relax. You are sooo lucky.
Once you get to a certain point in your pregnancy your levels no longer follow the "doubling rule". They are still increasing so that is great!
How far along are you?? With your HCG levels at this point you should be able to see a great deal on a ultrasound!
Gemz- your doctor draws blood to measure your HCG levels, you cannot measure your levels on your own.
as long as it is going up and not down its not usually anything to worry about. see your doctor if you are worried. and i was just wondering how do you test your own hcg levels can you buy summat?