You just need a 'reality check' or some sort of motivator. I was the same way all throughout highschool and beginning of college. Coasted through my AP courses, got A's and B's without trying. Went to college, tried the same routine... and realized college actually requires more work. My grades dropped and my dad threatened to stop cosigning my student loans if I didn't bring my GPA back up.
He also gave me a talk about who I choose to be friends with. If you surround yourself with unmotivated slackers, you will be an unmotivated slacker. I shed my old friends and found new ones within my classes, who are of the same major. They're all motivated and innovative individuals who are looking to succeed.
Since then, I raised my GPA from a sub-2.0 to above a 3.0, got my first internship, graduated with a bachelors degree, web development certificate, and a 3.5 GPA, and landed a software development job with a large company making a respectable salary. I feel more happy with myself than I ever have, and the money's a bonus!
I think you just really need that 'motivating' factor, something that inspires you to succeed, to set and reach goals.
I hope you figure things out, because once you do life will be so much easier! Good luck!