Think of how much damage you've done to your brain and body with alcoholism. It takes time to repair and balance out the chemicals again. The first time I went through withdrawals, it took a solid month before I felt "normal" even though I still wasn't sleeping well.
A friend of mine who has been sober 10 years now said it took him over a YEAR for his sleep to be normal. It'll take time, just keep the faith and trust that things will work out if you stick with it.