Not acknowledging my ADHD until I was 31. I'm 33 and finally understand why my mind completely shuts down when I have multiple tasks, why I run from challenges

Not acknowledging my ADHD until I was 31. I'm 33 and finally understand why my mind completely shuts down when I have multiple tasks, why I run from challenges when pressed hard, why I failed classes multiple times despite understanding the material, why I always thought of myself as lazy and why I would have bouts of depression every time I tried my hardest at accomplishing a task. I've wasted so many years in a state of wonder at other people's lives - going on Facebook, Instagram, Reddit and reading about the great things people have accomplished, daydreaming that I wasn't a lazy bastard. It's also affected my hobbies - reading, writing and playing guitar. I just can't focus on anything for extended periods of time. My songs are disparate parts cobbled together. My writing is a bunch of snippets. If I read I go crazy and can't stop, if I start and get interrupted I never finish.