Is there a counselor at your school you can talk to? I agree that some sort of professional to get help from would be good. (Most all of us here for awhile are probably in therapy or have been in therapy at some point.) I can see why that school led you to be more laid back about your studies. And even moving to a new school can be stressful. Depression can also cause the inability to concentrate. And now you're getting yourself into a vicious cycle by getting depressed about your future. We need to get you out of this situation and back on track!

Please keep us informed! (Could you talk to your teacher(s) about what's happening, too?)