I want to quit my job after 5 days and I feel like a loser

So I graduated high school in April, I passed my exams in May. I wanted a job to save money for college. My dad found me a job (it's not that I couldn't find one myself, he just did it and surprised me one day) in production. At first I was like "okay, why not?". I knew it would be difficult because 1. It's my first job 2. It includes a ton of physical activity 3. I would be working 8 hour shifts.

I have been warned that the first two weeks would be more difficult due to adjustment etc. But ever since, I've never felt more of a mess. Five days have felt like a month. In the first two days, I had pain in pretty much every part of my body - I'm not exactly a fit person. I've become increasingly more stressed, overwhelmed, unwell, and anxious. I can't keep up and I know it's because I'm only just starting and I've been telling myself that. It's just misery after misery, I'm terrified of the people who work there, I live with the daunting idea that I'm not getting a hang of anything. There are people there who are awful and rush me when I'm doing my absolute maximum. I'm constantly dizzy because it's hot and it's 8 hours of monotonous work.

I have general anxiety disorder, I've been socially withdrawing my entire life, I'm medicated but I'm losing appetite with each day at this job, I'm just completely losing my mind and I'm on the brink of tears these last two days.

I feel like I'm such a loser because not only have I graduated late (I'm 20), I still feel like I can't push myself out of high school life, but I also feel like I can't even handle a job. I'm scared about my job now and whatever job I find next. I don't know how to handle it. I don't know how to communicate with people, I feel useless in every region. How am I supposed to hold a job? Or even find one?

I don't want to break it to my dad that I want to quit after only 5 days. He'll just tell me to push through because I get paid a lot. I don't want to disappoint him more than I already have with my life. I barely know how to handle responsibilities, I don't know how to adjust or handle anything. I feel like such a loser.

I know people would judge and laugh at me. Because I'm a stupid highschool graduate unable to handle the adult world that I have to face. I don't know what to do. I really want to quit this job, I don't even know if I can handle the week i would have to work before I officially leave. What do I do in this situation? Do I push through a month? Do I leave and find something less overwhelming? I know that I might be a spoiled person entering adulthood and expecting little work. I don't want to seem that way, but I am scared that this is what my life will look like and that I'll never find my footing.

I'm hoping someone here could tell me something, or suggest what to do or what you think about this whole thing. I need advice please.