Anxious To Go To Work

So I'm working at a very popular coffee shop on my college campus I'm relatively new and I just hate going to work there. My boss is strict and lectures you for a pretty long time about the smallest things. I get anxious even a day before going to work and get scared when I want to ask for help. Yesterday I fucked up pretty bad on something so I know I'm gonna get yelled at next time I go. What do I do....How do you handle this. And I am trying I study for my job before I go to work and try my best to do things right. Yet sometimes I mess up and get seen as an employee who doesnt take things seriously...I'm a full time student by the way