I went from LTC to acute care. Found myself faced with much of what you seem to be faced with. A couple things helped in my case:
1) got a diagnosis and stimulant meds, because there was a "ditz" factor that scared me, when I would do something careless, despite efforts. Meds really helped me focus, as well as tune out interpersonal chit-chat that tended to distract me from my job
2) approached unit nurse educator for specific time management tips. She spent 3 shifts with me, came up with more suggestions and lots of encouragement
3) Learned to delegate as needed.
4) Made it a point to learn and know what resources were available to me. After being the sole nurse in the LTC facility to being one of hundreds in a large hospital, it required effort to identify what I could and should do, and what could and should be farmed out to the team. Diabetes education, for example, which is so comprehensive it could take all day, even with a motivated patient.
5) Really internalizing the difference between a charge nurse LTC role and that of a staff RN in acute care. ADHD people are often great at getting the big picture and properly advocating for patients. In LTC, that role is so much more limited. Task-orientation should not obscure the big picture, or patient advocacy.