We must have had our wires crossed, because I thought the meeting was tomorrow, not today.
Должно быть, мы перепутали провода, потому что я думал, что встреча завтра, а не сегодня.
Definitions
The phrase '(someone's) wires crossed' means that there has been a misunderstanding or confusion between people, often due to miscommunication. It can also refer to someone being confused or mistaken about something.