For a long time I felt (and now feel) the same as you. I just wanted to share an experience that, while completely anecdotal, is perhaps atypical, and has been one of the defining experiences of my life.

I got the Internet as a birthday present on my 8th birthday, and pretty much disappeared from normal society for the next few years. The Internet was (and is) fascinating - I could learn anything, interact with people I'd never met with, and, notably, do adult things without anyone doubting me because I was young.

But as I got older, the Internet, and therefore my mind, just got busier. Eventually it was not only random articles and a few chatrooms, but dozens of apps and sites that are programmed to give us a dopamine hit. Being online to me feels like walking around in a casino trying not to gamble.

I don't think I concentrated on one thing for more than 20 minutes for years, and outside of school I didn't have to. So I just convinced myself that school was archaic, skipped as much class as I could, and ended up a mental butterfly. It was working for me.

Except for when I wanted to get stuff done. I probably started learning to program 100 times, but I would get distracted with cat pictures or something, and even though I loved computers more than anything else, I couldn't do much to create with them. I was diagnosed with ADHD, but I didn't really care; I don't think that experience is unique to either me or people who have been diagnosed with ADHD.

Then, all of the sudden, I went on a Mormon mission in eastern Ukraine. Two years with 30 minutes of Internet a week (at an Internet club 45 mins away from my apartment). My entire life was structured in a way I never would have structured it in order to get me to concentrate on the things I considered most important for that period of time.

My mind slowed down - in an almost literal sense. I had only finished a couple of books in my entire life before the mission, and on the mission I could easily read the Old Testament for hours on end, paying attention to intricacies of text I never would have realized before.

Then I got home. I jumped on Facebook, and right back into my old habits. My mind was gone for weeks. Not gone in the sense that I wasn't learning anything -- I would pick up tidbits here and there, but I never got deep enough into anything to make any of that learning useful. It terrified me.

So now I spend a lot of time on very strict information diets. I severely limit my time on HN, Reddit, Facebook. I try to keep my reading on a Kindle so the Internet isn't even an option. I would love for someone to create an app (that works) that limits what sites I can use so I can go into "wired in" mode when I'm programming.

In short, don't be afraid to place restrictions on yourself. Let your mind slow down.