I don't think being distracted from things that don't interest you is necessarily bad (although, it's definitely impractical when school is all about getting good grades on everything!), and it doesn't necessarily mean you're not aligned.
I have ADD, was on Ritalin for 4 years and stopped it about a year ago. I feel much more aligned now (Ritalin suppressed a lot of emotion, and gave me tunnel-vision), although I definitely have trouble meditating - but I manage by practising mindfulness in little bursts whenever I can. And I am constantly working on 10 different creative projects, which has caused problems when people have tried to sign me into a long-term commitment (e.g. record deal), but I'm done with trying to conform to what's "normal".
I met someone recently who also has ADD - she does 8 jobs professionally, and just lives her life based on what she feels like doing. It's unconventional, sure, but, we have unconventional brains. :) And I think we incarnated in this life and picked that brain for a reason! So it's something to embrace and figure out how to use it as a talent. I just make sure that whenever I'm distracted, I'm distracted by something that I am passionate about, and I avoid watching mindless TV or procrastinating. Because of my constant distraction, I've ended up pretty darn good at quite a few things. So ADD is definitely a gift!
As for schoolwork, that is a tricky one. I always had really good grades in school (this was before I started Ritalin), even though I literally didn't listen to anything that was going on in class. I basically just learned everything in my own time, and took lots of breaks if I felt distracted.
Is what you're studying your passion in life, or just something you need to get through before you pursue your dream? If it's your passion, there must be a way you can make the subject matter interesting. If it isn't, then I guess just reassure yourself that your life is so much bigger than what grades you get in school, and that you'll find your true purpose some day. And ADD will be much easier to handle once you're out of school!