i'm not designed for this existence

I can't fucking do this man. I'm 19 and 2 months ago got my first fulltime job. 8-5 everyday, how the fuck does anyone do this?? I'm miserable all the time and am too tired in the evening to do anything, so I'm just stuck fucking working and working and working and it's killing me. I haven't thought about suicide this much since I attempted when i was 16, but at least there was some form of hope back then. Now I realise that I either have to get used to working myself to death forever or just kill myself now. Surely everyone is suicidal and just pretends they're not and are too scared to do it?? How can this existence make anyone feel any other way i just don't fucking get it

when i was 16 I told my therapist that even if I do get better, i'll probably end up killing myself somewhere down the line, probably early 20's, and it's looking like I was right.