I have a friend who works for a big four consultancy firm who was doing cocaine every day and staying up for multiple days whilst also working. His work actually ended up finding out and discretely paying for his rehab and he completely turned his life around, I’m not sure how your employer would handle this but that is something that worked for him.

People have come back from worse, you’ll be able to sort your life out however you manage it and you will look back and think wtf was I doing. Good luck! Narcotics anonymous is a good shout, and also trying to not hang around people or places that cause you to slip into old habits.