on one's mind

adjective2

1. •
   In one's thoughts, especially persistently or recurrently.

   • Oh, Ophelia You've been on my mind, girl, like a drug Oh, Ophelia Heaven help a fool who falls in love — 2016
2. •
   Causing worry or preoccupation.

prepositional phrase1

1. •
   Preoccupying someone; present in someone's thoughts.

   • She had been on his mind since they met at the bar late last night.