It is tough with school, I understand. I actually left my waitressing job in October because of my credit load. I was out of work for about 2 weeks (remember, DH is working) until I found an ad for a nanny in the laundry mat. Now here I am! My boss at the restaurant is begging me to come back, which is a nice ego boost.
It's a fine dining place with a small staff that has been there for awhile. Newbies don't last much longer than a week (sometimes less than a day). With a staff that size, you work many shifts, and you have to actually CARE about the place. The place has 4 stories of tables and no dumb-waiters (no jokes here!)

. It's a lot of work carrying 30 lb trays of food at $35 a plate up 3 flights of stairs and not look sweaty!
I love the job, so I'm gradually stepping back in. I love the customers, the atmosphere, and I'm in with the chef (always a plus)! Finally, I'm taking a wine-making course at school which has expanded my always-abundant interest and knowledge about wine. I'm making blueberry this semester!
ANYWAY.....my advice, take a hiatus. Don't burn any bridges. Leave it open for you to come back too. Most employers, even the most demanding ones, understand the stress of college.
HANG IN!