Have one of my favorite screenshots:

http://images.akamai.steamusercontent.com/ugc/35240698131830586/99DD0FF1BB47E2325B923621E074E5B0732E8005/?interpolation=lanczos-none&output-format=jpeg&output-quality=95&fit=inside|1024:576&composite-to=*,*|1024:576&background-color=black

I used to beat myself up a lot about school too and couldn't find my motivation, especially in high school. Talking to guidance counselors and teachers about it never helped me. I think if I had gone straight to college out of HS, it would have just been more of the same. I took a couple years off and worked full time, though, and that shitty job drastically changed my attitude towards school and life in a way that just trying to fix my brain by thinking never would have done. It also prepared me more to "just do" shit I didn't want to do.

It might also help to be more patient with yourself cause there are a lot of pieces to being an effective student, and it's very hard to learn it all at once. When I came back to school, I set gradual goals. I didn't start out being a perfect student. First thing was first: to actually get every assignment turned in, even if I was scrambling at the last minute or the work was poorly done or whatever. I adjusted from there when I felt a bit more comfortable.

Another super important thing for me was finding professors I liked. I always look on ratemyprofessors.com early. (The best classes will fill really quickly after registration opens.) Finding someone with genuinely interesting lectures or someone you can make a connection with in questions after class or in office hours makes all the difference in the world. In fact, when you've got some leeway to choose your classes, I'd prioritize excellent instruction over the actual subject you take. If you're like me, a lot of things can be interesting, and I think that for most people, stressing over finding the subject to study is a bit misguided. Some are definite poor fits, but there are actually lots of fields out there that a given person can do well with and every single one will be dull or hard sometimes, so it makes sense to take advantage of what departments are known to be really good at your school.

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Ultimately, these are things that helped me, but your own situation is highly individual. There will always be ups and downs, so just keep patiently looking for clues to what motivates and demotivates you, and be open and unafraid in considering the implications of what you find. Best of luck, dude. :)