I have had the same problem forever, and it was made worse when I started with ritalin a few months ago. I think it’s a multi-part cure, including a lot of self-talk and reminding oneself of priorities (not the easiest thing for an ADHD brain obvs!) and repeating behaviour changes over and over. But a MAJOR help for me has been marijuana used medicinally – the stuff with high-cannabinoid (CBD) and low-THC (the psychedelic part). You have to be careful not to get into something interesting like the internet or a book once you’ve taken it, but it really slows down my mind and stops my need to keep doing, doing, doing out of habit… relaxes my body, slows my breathing. It was a revelation to discover how much it can help, as I’d stayed away from pot my entire adult life. BUT MAKE SURE YOU DON’T USE HIGH THC CONTENT POT… it keeps me awake like nobody’s business. Also you can get high-CBD oil that is even more physically relaxing and has less get-you-high potential. Hope this helps.