Toughgirl,
Don't give up on sleep. It is not overrated. There are times when it is not possible though and use them to your advantage when sleep eludes you. But keep trying b/c 1. you can never actually 'make-up' sleep by getting more of it later and 2. it is SO critical to get it. I know you've said you've tried everything but there are things in your daily routine which can make a difference too which can alter your patterns to cycle you back especially if you are experiencing drowsiness during the day. This is a good indication there are other things that might help. Please consider this.