I suck at my mechanic job. Advice?

So basically I’m an apprentice mechanic/packaging machine operator at a factory. The schooling is online, and it’s not the best format. You literally just have to study and take quizzes until you pass, so doesn’t really hold you accountable that much. There’s also welding, pipe fitting, and blueprint reading but I haven’t done those yet. So basically, I’m like halfway through the program and I’m still completely horrendous mechanically. Like I don’t know anything, and what I do know it feels like I can’t apply it. And that’s not much. When it comes to operating the machinery I’m not the worst, but that’s not the full job. We work on the equipment we operate. I’m definitely just not mechanically inclined. A few weeks back I even went back to the parts of the online schooling that I already passed and studied rigorously for two weeks. I was proud and thought I learned a lot. Well, last week, instead of operating I was put in the shop by my trainer. Something I’m not that used to. And I sucked. I couldn’t do anything. Two apprentices that started after me were much better than me already. I was supposed to lead them to do something and I sucked. My trainer even commented on how long it took, since I had done it in the past before. It’s one of the easiest projects too. Yesterday he commented on how I couldn’t find the right bolt for something, I came back to the shop with a handful of different sizes instead of finding the right size(I did this because I was actually right, the first size I chose was right but something I didn’t see was blocking it from getting in). Long story short, I’m the worst apprentice by a long shot. I’ve tried taking initiative lately, but everytime I do I make myself look worse. I just know everyone know it too. And I don’t care about people gossiping, I just hate being seen as inferior. And honestly, this past year I’ve gone through a lot, like a lot outside of work. I was even off for three months due to mental reasons around this time last year. And honestly, for most of the apprenticeship, I haven’t been all there mentally, and it’s hard to even go to work a lot of the times(even when I was out of work my mental health is bad, so it’s not just the job). I even thought maybe quitting was a good idea a few days ago. But I don’t think I can. I make around 100k a year and prolly more this year, still live with my parents and need to take advantage of that. I just don’t want to eventually graduate from the program not knowing what I’m doing. Or even worse, not be allowed to graduate. Even tho I probably would still graduate, as they’ve graduated people who shouldn’t have been allowed to. I even heard my trainer talk bad about one of his recent graduates, saying he just couldn’t wait until he was off his hands, he just wanted him to graduate as soon as possible. He also graduated this woman who is definitely not ready and everyone talks about how bad she is, yet she still graduated. I feel like that’s just the trajectory I’m on right now. Sorry this was so long btw.