Wiktionary
on one's mind
a. 1 In one's thoughts, especially persistently or recurrently. 2 Causing worry or preoccupation.
Usage examples of "on one's mind".
Such an impressive individual, who had given so much to human culture, would surely have had a lasting impact on one's mind.
How terrible to be a man, and to have sex on one's mind all the time, as men are supposed to do.
Truly, nothing is worse than waiting idle, while fear preys on one's mind like ravens upon a corpse.
It was polite to talk about lesser topics before discussing what was on one's mind.
If one has that sort of compulsion, one naturally writes about things that have made a strong impression on one's mind.
Hiroshima impressed itself on one's mind as a vast expanse of desolation.