to be greatly perplexed; to be at a loss; to be sorely troubled; to be greatly embarrassed
予定が合わず困り切っている。
I am at a loss as the schedules do not match
彼は借金で困り切っていた。
He was in great trouble due to debt
言葉が通じず困り切った。
I was at a loss as the language did not work