I weigh 125lbs and take 10mg in the am and another 10mg around noon time. People can react differently to meds so maybe your dr. is being cautious and that is why he has you starting at 10mg.
Do you take any other meds or have any other medical issues? Adderall is an
amphetamine so maybe they are wanting to make sure it doesn't increase your heart rate or something like that?
Not to mention........Adderall may not be the "answer" for you and you might have to try a few other meds before you find the "right" one. Give it a few days and if you don't see any improvement -- call your doctor.
take care