Should I Quit my Part Time Job to Focus on School?

I am currently working in the food industry for minimum wage. I am a community college student that is trying to save money for my higher education. However, with final exams coming up soon and my chemistry grade slipping, I am considering quitting my job to focus on studying full-time. I currently only work 15 hours a week for two days of the week, (sometimes 22 or so three times a week) however, my job leaves me feeling drained and tired and I lose having those days to study.

Not only that, but my manager is degrading and constantly threatens and insults me, which I am beyond tired of. I have only been there for four months, and although I am attached to my coworkers/used to the job, I think leaving may be best for me. I am taking 5 classes with a total of 17 units and have straight A’s except for my chemistry grade, which I need to raise a full 10% in order to get an A. Even if I get 100% on the remaining assignments (exams and final included), I will only get to a 93.3 (I need an 88 to get an A and currently have a 79). I’m a good hard-working student - I think if I apply myself I can really get that A. I want to go to medical school and chemistry is my major, so I am worried that this will affect me negatively.

It’s my first semester of college and I don’t want to slip up so soon. I’m super stressed out over this because I did want to save some money for school since I have a large family and need to be somewhat financially independent in two years, and my public school tuition is going to be 40-60k for two years, and then even more for graduate school. However, I am still living with my parents and I don’t have any bills to pay - this is all savings. I go to community college for free so I only need to pay for textbooks and even that is very minimal cost (100 or less/semester). My mother encourages me to quit my job and prioritize school, but I know in the future when I am cash-strapped I may regret doing so.

I wish I could take just these next two months off but I know that is ridiculous to ask for. I need to put in a two weeks notice before quitting and finals are in a month and a half so the sooner the better. I really want to quit at this point but I am no where near saving as much as I had planned to and I have just gotten to a point where I am done training and understanding my work completely, and I know that my manager needs my help - we have a busy place and without me there she is understaffed and cannot run her errands, so I feel bad about leaving so soon. Any advice would be appreciated, thanks.