I really struggled with this when I was in high school, I was so burnt out. I became quite socially isolated because there was no-one there who I could really relate to, and all my friendships felt superficial and not worth the energy they cost.

For me, it got a lot better when I left school - at university, I met so many more like-minded people and that helped massively. I also was quite lucky to genuinely enjoy my degree subject, but I've also seen people who aren't keen on their degree in practice, but they too find solace in their community. I lived in a shitty, backwater town so it feels like my life didn't really start until I got out of there.

In terms of how I coped during that shitty time - I didn't. Like I say, I ended up withdrawing even more, and eventually I got so burnt out on the school structure itself that I started skipping lessons; I got in trouble for it, but I was too depressed to care. My grades were still decent, because self teaching was more efficient. This isn't advice, because I don't think this was a good thing to do, it's intended as solidarity, because school really is shit — as an adult, I've found that the best way to cope with depression and suicidality is to claw back as many fleeting moments of agency from the world as possible. School is so incredibly disempowering though.

There are a lot alternatives out there to the way of life you are describing. It seems like that's the only way since that's how people around you live. But if you look a bit outside of your circle - you will find people living other lives. They also have their own problems - but what you see ahead of you, is not the only way.

This is just a random thought, and I may not be understanding your situation correctly, but does France have anything like the GED? Sorry to hear you're having such a tough time.