Is there anyone out there who takes Ambien for sleep and has to take two 10 mg. tabs for it to work?

Ambien does work for me, as I have a hard time falling to sleep, staying asleep is NOT my problem, but I don't want to tell my doctor that I have to take 20 mgs. if it seems to unusual. All bodies take medicines in different ways, I just needed to know if I am unique to this situation. Any help would be great, thanks!