I have ADHD, an executive functioning learning disability, anxiety and some depression as well. Your symptoms seem similar to mine ADHD-wise. I would go through the testing process. Get started as soon as you can. Even if they decide it isn't ADHD, you can still get help with school/therapy/coaching. And if it is, then you can definitely take hold of resources. Since you are a high school student, you probably have a lot of resources available through your school. I'd maybe start with your parents and ask them to help you out, or even your guidance counselor. Good luck. Remember, it's more important to take a small risk and get the help you need rather than wonder or struggle in silence. That's neither fun nor productive. I'm in college now and I wish I could have had more support earlier on. Go get it, kid. You can do it :].

PM me if you want some more support :].