If the thing you're needing to do is a Big Scary Serious Task, pace yourself. I've been overstretched in recent months, and I fell into a pattern where I would keep cutting down the things I was trying to do. The first things on the chopping block were the "non essentials", the things that were strategically important to the task, but made me happy.
Now I feel like a husk of a human and I don't have much I can do to cheer myself up when I'm having a bad day. None of my nice things are accessible. I've built a life for myself where the Tasks (TM) are all that exist. Ultimately, it's harmed my productivity, but I've discovered that too late. Now I'm fumbling to try build up the self care stuff while also struggling to stay on top of the Tasks (TM). It's a lot, and I have regrets.
Try not to fall into this same trap. If you're lying in bed, thinking "I should get up and do important thing", but dread paralyses you and you do nothing, then that's a materially worse world than if you had said "fuck important thing, I'm going to get out of bed and do this fun thing". Sometimes I would "allow" myself to do the fun thing, but I'd feel guilty about it, undermining it's benefit. Let yourself be where you're at, because bullying isn't going to fix it.
It can be hard to distinguish between self harm and self care when things are rough. I'm not talking about physical self injury self harm, but things like staying up late to play video games. Whether it's harm or care depends on the circumstances and I have had situations where I've lied to myself and said that giving myself that extra slack is self care, when actually, it was just avoidance dressed up nicely. It's exhausting to always be second guessing yourself, so my biggest advice is to be kind to yourself on a meta level - sometimes you're going to make bad decisions that make things harder for yourself, but remember that you're trying your best. Even making this post is an example of you trying.
It's not your fault if you need more support than what you're getting in life. Try to remember that. It doesn't materially change anything, because life's pressures will keep coming, no matter how we frame them. Just try not to be too harsh on yourself, even if it feels like your output is not enough for your needs. Things are often shit and the fact you're here at all is pretty fucking incredible. I know it's hard, and I know you're trying, and I'm proud of you. This part's addressed to anyone reading.