While I never has that hard dependency, I know part of the feeling.
It is hard. It does hurt. Any help is useful. And it is worth it.
If you don't manage it in first try, it is ok, maybe even usual.
I am happy for you at least eant to quit and you are doing your current best. Get any support you can and have understanding and love for yourself.
I would also suggest psychotherapy, it helped me. There is a reason we are addicted. Problem is good therapist is also hard to find, but it is worth it.
Good luck!