Fantastic work on one week!
You will feel energetic and normal ... soon enough if you keep at sobriety. Relish the sleep ... once I got over the insomnia the sleep was wonderful, fresh and sweet like I'd never had before. Well maybe when I was a kid.
The weight loss ... it can wait. One week in and your body is still thanking you for no longer poisoning it. Treat it gentle. Let it have the food it wants for now. There'll be lots of time to get the diet, exercise etc. in order.