OP, I've been where you are.
I've been awake at 3am contemplating whether it's all worth it.. really was my lowest point. Went downstairs to make a brew and there was a natural history thing on a podcast about early humans etc. I just liked background noise so that I didn't feel so alone.
But listening to it, I was struck by the weirdest thought ever - but it literally changed my outlook on life and still does!
Here goes..
Since the dawn of time, humans have been struggling - to find food, shelter, a mate, not be eaten by predators, fall off a cliff, get swept away in the river, die of disease, injury, or in childbirth. Obviously many more perished than survived, but we're an inventive species so we adapt and overcome.
And as I sat there, it dawned on me that even in order for me to be sitting there at 3am wondering if I could go on, I must in fact be the descendant of an unbroken chain of survivors! If any of them hadn't survived, the chain would have broken and I wouldn't exist! Weird thought I know, but it really grabbed me..
I opened the patio doors and said to nobody "not today world, do your worst by all means, but trust me today is my day and I'll choose what happens next, not you".
Literally jumped in the shower and felt better. Started making a list of things pissing me off and actions I could or couldn't take.
Decided I needed energy for this so prioritised self care first - you can't mow the grass if you've not sharpened the blade.
Kept it simple - sleep important, no crap foods and force some exercise to start retaining my body that it had more to do than just mope around.
And then just prioritised time into things I chose and stopped thinking / doing crap things with my time.
None of us are here for long, so may as well get in the mix and do your funky thang whatever the hell you choose that to be!!
Good luck, you're not alone.