well lack of motivation is a symptom(/product) of depression. i never want to do anything when i'm depressed. maybe talk to someone about it. i think if it was an anti-authority problem, you'd have good reasoning for not doing your work rather than you just really didn't want to. Theres not really a thinking process for what you are doing; its just like "i know i have to do this...but ehh" (which i do all the time). So my suggestions are: getting meds, or talking to someone who can help you control your level of motivation. Good luck!