Yes this is often true. It takes your body that long to build up the saritonen. (sp) You should talk with your doc and see if he can give you a sleep aide for now. When I first lost my mother, I went about a month without more than 2hrs of sleep every night. My depression was out of control. When I couldn't tell my therapist I could be safe at home, he had me hospitalized in the mental health hospital for the first time. Sleep deprivation adds so much to your depression. It is funny, the more you are depressed, the worse your sleep is, and the worse your sleep is, the more depressed you get.
BTW...Each anti-D is different, and they react different with each person. The time for your body to react to them, differs with each med, and with each person.
I would definately talk with your doc though, as you may need a higher dose. They may do some blood work to find out where you body is at.
Take care of you
bren