I feel similar, and I have been diagnosed with ADHD since the 3rd grade. I took stimulants off and on ever since then, nothing has really gotten to the core issues though. I have existential thought crises and often my mind races from topic to topic until I can't even remember where I started without working backwards. I write reminders and set alarms, which are a big help. The rest has yet to be solved, one step at a time my friend.