For anyone struggling with dark thoughts: you are not alone, and Allah's mercy is vast

Assalamualaikum everyone. I'm reaching out because I'm going through a really difficult time and I don't know where else to turn. Not long ago, I was in a place of such deep despair that I acted on thoughts I now deeply regret, harming myself in a serious way. By the grace of Allah (SWT), I am still here today. Ever since that moment, I can't shake this overwhelming feeling of guilt and fear. I'm terrified that because I had that intention in my heart, I have permanently lost Allah's mercy and doomed myself. I don't feel at peace anymore; it's like a constant shadow over me. I just want to worship Allah properly and feel close to Him again, but I feel so distant, hopeless, and scared that it's too late for me to be forgiven. My question is for anyone who has been in a similar dark place, where you felt you had reached a point of no return. How did you find your way back? How did you begin to rebuild your iman and trust in Allah's infinite compassion? I'm feeling so lost and any advice from the heart would mean the world.