should i quit?

i started working at a large retailer about a week ago. my first day was terrible and i ended up crying by the end of the day because the customers were so rude, and i was left to check people out on my own. my second day was better, but i got chewed out by my manager for not being at the register enough because i didn’t feel ready, even though i did check a few people out on my own i was still pretty shaken from the previous day. my third day was good, it was a monday so it was pretty slow but that was my last day of training so now i’m expected to know how to do the register on my own. thursday i asked to do recovery, because i enjoy organizing things and i figured it would be a way for me to look foreword to coming to work more since i absolutely hate being a cashier. i was able to for that one day and i had a pretty good time until i was supposed to do put backs with this one girl who got pissed off ag me every time i didn’t know where something went. since i was a cashier i was always required to stay in one spot so i never had the chance to move around the store and figure out where things go. i asked my manager if i could do more recovery and she told me that if she wanted me to have her even consider a position change i would have to do better. i don’t feel happy with this job and they didn’t prepare me at all. i dread going to work every day and they’ve given me more hours than most of the staff, which could be normal since i’m so new so i can get the hang of the store. i really want to make money, but i have to quit by the time school starts anyways, so should i just wait it out, or quit now? it’s really weighing down on me but i don’t want to be a quitter!