to think too much; to be over-concerned
彼は考え過ぎたため、締め切りを逃した。
He overthought it, which caused him to miss the deadline.
彼女は考え過ぎて、ぐったり。
She overthought it and was utterly exhausted.
些細なことまで考え過ぎる自分を変えたい。
I want to change myself — I overthink even the smallest things.