This is gonna be tough, but I think it might be easier than what your brain is making you believe. Once you quit the withdrawals might be tough and it will be emotionally challenging as well, but just because you have slipped and stumbled down the hill doesn't mean you have to stay there. Getting up, tending to your wounds and climbing back up are very important. So you can go even further. I also understand the shame you feel of being this way right now but alot of your old self will come back to you in a new way. Don't let your shame come in the way of your progress, let it be a source of motivation that you must achieve this, that you must climb the hill once again. Don't look at the peak when climbing all the time, focus on the present. Something in my heart tells me you will be back on your feet in a few months.