My girlfriend suddenly sent me a message saying good night last night?

If an ex-girlfriend suddenly sends you a message saying good night, first of all, if he says that he suddenly finished talking to you, it is very likely that your ex-girlfriend wants to get back together with you. This is a composite signal, but if he sends it to the wrong person, then this possibility is ruled out, but basically he sends it to the wrong person. Since the ex-girlfriend took the initiative to talk to you, it's probably now.