Is it normal to have to pick up jobs for someone who’s paid 11k more than you just cause they feel like not doing it?

I feel like I’m treated like a slave at my new job and literally squeezed until the last drop. I already have anxiety from it which came from my doctor’s diagnosis and they said that they didn’t care and that I should continue working. I would love to work in a retail/costumer job instead. I hate my life atm.