I'd like to start by saying, I can appreciate your willingness to work while in school and trying to get your degree. I can agree to an extent that an employer, hiring mostly college students should be a little lenient with his/her employees. My argument is that, THEY are the employer, and YOU are the employee. They hired you to get a job done, not to give you a job where you could sway your schedule to fit your needs. I'm sure that like any business, they are in it to make money, and with employees not there, they aren't making money. I can sympathize with your situation, as I've been let go from a company for coming in 10 minutes late, when it was verbally agreed by my immediate boss that it wouldn't be a problem if it was only once in a while. I took it as a learning experience, as employers generally aren't out to be your friend. They're there to run a business, and it's not going to phase them one bit to let you go. Hopefully you can explain your situation to your boss and possibly work something out, where you can work for them for the remainder of your college career, or atleast until you find something new. Good luck with it all.
Mark