Communicate. Your everyday boss - who probably senses something is wrong - will be able to find a solution for you. That's part of her job. It might mean trying to keep you on and rearranging things for you. It might mean you give a two-week notice, or shorter. Maybe you get fired on the spot - not very likely, but you're ready to quit anyway, and it would be a mercy. You won't know until you talk about it.
Also - since you're young and not terribly experienced - don't worry so much about what your employer deserves out of you. They will take everything you give them - all of you, if you let them - unless you set boundaries. This is the nature of many relationships, business ones included.
And yes, I've quit jobs with short notice before. In those cases, I wanted to stay longer and see the business to success, but it had to be done. Everyone was better off, every time.