That one night away likely caused your supply to drop because the demand dropped suddenly, and your body responded by making less milk. The most reliable way to rebuild is to increase demand again, so nursing or pumping more frequently, even if the output looks discouraging at first, really does help signal your body to catch up. Some mums here also find that power pumping (pumping on and off for about an hour to mimic a cluster feed) helps over a few days. It might also be worth checking in with a lactation consultant or even your PD, just to rule out anything else and get personalised advice on whether what you are taking is the right fit for your situation.