I think it all begins with honesty and courage. Accepting that you're a sinner, that you aren't as flawless as you make yourself appear to be. That you needed help. That you needed to stay away from every broken relationship, as to save yourself from drowning. That enough is enough. Stuff people! Because it's you that need saving, not them.
With honesty, comes reflection on oneself. And with reflection comes the practical bits. The last resort would be courage, as you lay out the plan in front of you and implement the changes, step by step.
Yes, starting over would take years! You'd need to figure out what kind of person you want to be, what company of people would you want to hang out with, daily routines, new and re-furbishing hobbies, your level of intellect and etc.
One of the hardest though is to stay guarded, all the time, so as to not deviate back to your old ways. That's why you would need a lion heart, to do this.
It's the knowledge that you can, that Allah is there for you for your positive changes and that the people that stayed with you, despite everything are there with you the whole time. These will be a starting point to your breaking point.