So I'm living and going to school in NYC. I live about a ten minute walk from campus and I carry my school supplies in a messenger bag. I also carry a few everyday use and emergency supplies:
Thermos
Clifbars
Washcloth
Sunglasses
First aid kit (trauma bandage, nitrile gloves, bandaids, aspirin, Benadryl)
LED headlamp and extra batteries
Spoon and chopsticks
Reusable shopping bag
Change
Notebook and pens
Swiss Army knife in my pocket

Suggestions?

Be mindful I don't want to break my back carrying it, I'm a student without many funds, but I have a decent inventory of camping supplies.