I’m so sorry to hear about your break up and your mum having terminal cancer. Please Don’t go back to addiction. You have enough to deal with already and that will make your life much much worse for you in the long run. You really deserve better than that, dont you?
Can you spend more time with your mum? Time is precious just now. Make some happy days for her? For you both?
Keep on with moving forward for your future, and for her now .