I've fallen off the Cliff of Hope and bashed myself on the Sharp Pointy Rocks of Doom and Despair over the last few weeks

Feel slightly mechanically better now, since I did go to hospital and will hopefully get referred to the community team, because it feels like taking an action as opposed to lying back in a frozen heap using all power not to binge/cut/worse stuff.
But I wondered. For the last while, before this blip, I'd been doing a lot better in general at taking care of myself - eating, prioritizing health, not beating myself up over stuff I've failed to achieve, etc. And, I dunno, all that energy poured into caring for myself better - it didn't make any difference really, to how I felt

I felt silly, in fact. Why bother looking after myself well, just to sit in my room longing for my mother to be alive, feeling desperately isolated from the world.
When you aren't important to anyone but yourself, what keeps you fighting stubbornly on?
I think this is the bit I have trouble with figuring out. I have lots of interests if I could make the effort to engage with them, I love my job, I know that I have some good talents I could gain a lot of satisfaction from. But I can't commit to life 100%. How do you commit?
Maybe I'm asking from the wrong side. What are the everyday things that really help you when you are feeling low? What lifts you? Eating really healthily? Exercise? Omega oils? I thought I was doing ok, I kept my diet reasonably strict and got some exercise everyday, and although I felt a sense of control and pleasure at keeping my **** together and going through the motions of a reasonable balanced human being - it still all felt pointless. Like why bother taking care of myself, because I still felt in incredible pain every bloody weekend after my therapy session. My sessions were the only place I could admit to the pain I felt and then there was no escaping it until I got to distract with work again.
So what do you do, what everyday things, that makes a substantial difference to your wellbeing?
Have you ever felt that not harming yourself was 'as good as it gets'? How did you get past that?