Usage patterns
〈事〉が気がかりだto be worried/concerned about something
I'm worried about where my daughter will end up working.
〈事〉が気がかりで〈動詞〉to do something because a worry is weighing on one's mind
I couldn't sleep because I was worried about the exam results.
気がかりな〈事〉a worrying matter/thing
There's one point that's bothering me.
〈人〉のことが気がかりだto be worried about someone
I'm concerned about my grandmother who lives alone.