Hi, I know I'm late but I hope you're doing better now. Last year I was in the exact same position as you now, I knew I was going to fail my A levels and what did it matter anyway because I was going to ctb regardless. Fast forward to results day, and it was the worst day of my life. The combination of my life situation and my results pushed me to the edge, and resulted in an attempt. Unfortunately, I was caught by my brother. I used 'unfortunately' as since then my life hasn't really changed for better or worse instead it just stagnated.
I took a gap year, applied for resits, and am now awaiting my results again. What I'm trying to say is to take your time. I'm not sure of your personal situation but, take as much time out of education as you need to and focus on getting better. Those 2 years were the worst out of my 19 years on this earth, and by taking a year out, I finally am starting to feel somewhat like myself again.
Yes I struggled, I still am, funnily enough I'm still committed on ctb. But, it's important to not fuck up your chances in life because you may never actually ctb. You'll just have bad job prospects whilst being suicidal, instead of having good prospects and being suicidal.
I cried to your post, it reminded me so much of me I just had to respond. I know exactly how rough it is, and I feel for you. I really do. I hope you're in a better place now, or have found peace.