"Last night" is the phrase that you use to talk about something that happened on the most recent night when counting back from right now. But when you're counting back from some time in the past, you use the phrase "the night before". Here are some other time words that change depending on whether you're counting from now or from a time in the past or future:

• today > that day
• tomorrow > the day after / the next day
• last week > the previous week
• next month > the following month