I was still working at the checkout in a supermarket at that age, and I dropped out of university because my mental health was plummeting at that point and I hated it and I hated everything else I was dealing with. I beat myself up for a while about that, which was also not great for me.

I hear you, it's a frustrating and hopeless-feeling experience for sure. All of us older people are coming in to say it's not a big deal. They're right, in the grand scheme of things, because they've had the extra years to realise that. I have, too. But you haven't and it's a raw feeling, so I don't want to be dismissive of that.

Nonetheless, there's a lot of support in the comments here, and it's worth a read to see what you can relate to.