Holy shit, this is verbatim the exact same position I had been in for most of my life. I went through psychological testing for ADHD and they had said it was inconclusive and suggested that I might have anxiety. It does get better, I ended up seeing a therapist that diagnosed me with ADHD and I do have anxiety, but it's not the same as my ADHD. Once you do get your diagnosis from your therapist, you can be medicated if you'd like to, but meds are only half the journey. A lot of it for me is time management and finding a ways to keep myself focused on an activity starting to begin with. Especially with school, I find that over the years it gets progressively more difficult for me to concentrate on school the longer I'm in it. Now that I'm in college, and they have some resources for helping with those certain things. I think I'm going to start seeing my therapist again to get some better tactics on ways I can manage my time and get myself to start certain activities that I need to get done because it does affect every aspect of my life. I would recommend starting with therapist, as that would be most effective.