It hasn't been easy doing something I've never did before learning something new without letting the one in my mind tell me that I'm fucking it up

It hasn't been easy starting my new job and feeling like I a burden to everyone around me because they have to help me dealing with customers that get mad at me just because their change is off by $0.03 it's hard because when people make me feel like a screw up when I already have the one in my mind to do that for you you don't need to tell me how I messed up she already does I don't like it when people point out that my hands are shaking that I looked scared I am fucking scared I've never did this shit before I'm not a master at the cash register I don't know everything there is to know I've only been there for 4 days but the customers treat me like I should know every single detail meanwhile everybody around me is telling me I'm doing fine and that I'm doing good but you don't know what's happening inside my mind you don't know that my anxiety is telling me that I'm going to screw everything up you don't know and I'm trying not to listen to her and I'm trying to tell myself that I'm only making it worse for me by listening to her and that I don't deserve to listen to that as much as I don't want to feel this way as much as I don't want to hear her it hasn't been easy