Believe me you are not a failure in anyway whatsoever. Look how many people have fallen into the codeine trap, it happens very easily. The point is you are now trying to get clean and that’s amazing!
Could you maybe see your GP and explain what’s been happening, they would be able to give you a short term course of sleeping tablets. Completely understandable if you don’t want to share with your doctor, not everyone does. I just know how much harder everything seems when you can’t sleep.
Either way, keep going you are doing so well, try a hot bath before bed. Some people have said magnesium helps too.
Please don’t beat yourself up, be kind to yourself and be your own cheerleader! What you are doing is hard work. Sending hugs ♥️