Helpp meeee

Alright, well recently I've been having motivational issues with myself involving school and other various things. I really, really, don't know why, but I don't seem to care (no matter what my mark is) how I do in school. I honestly don't get it. I want to get a great average, go to university, and get a degree, but none of that seems to motivate or inspire me to do well in school now. Exams are coming up, and I have told myself since Monday that I will start to study for exams... I haven't even attempted it. I truly believe that this year is my worst year for school. I have yet to do any homework, what-so-ever, at home ONCE this year. Regardless of how stressed I get, or how much the homework may be worth, I still just do not have any motivation to get off my lazy fucking ass and get to work. I hate this part of me, the procrastinating, lazy, uninspired, kid who puts games before homework, family, girlfriend, and friends, part of me. Do you ever just have one of those days where you need the day off to relax and not think about school or anything? Yeah, that's what I have every single day. It's not as good as you may think. Actually, I'm 100% sure that it's the worst thing that has happened to me. I'm 18 now, I'm not a kid, I'm offically an adult. Does that mean I should be doing homework and be worrying about my future? Yes, yes it does. Have I been doing that? No, no I haven't. This is a little bit of a rant, but I honestly don't care, why would I care about ranting when I could care less about my FUTURE. Anyway, this leads me to a quesiton, all answers (if any) are good. What the fuck should I do? I really need to get my life figured out and stop being such an immature scunt of a kid. 18! 18 years old and I'm as mature as an 11 year old at my best. Fuck, I'm a wreck! Good times. Good times.