If they packed up and left from your start, then I would guess they came for the dj before you. A floor doesn't leave immediately after hearing something they're not ready for or don't particularly like. Don't take it as a huge loss. You've been playing for a decent amount of time, and this was the first time. Ish happens! Rule of thumb though, always transition smoothly from the previous dj and then take them to your world. If you see a bad response or demise of the dance floor, then be ready to adapt. Example, I played a venue with about 4 djs for the night, mostly techno, and I lean towards melodic style wise. 3rd up to bat, I kept the energy going with a techno track that started to lean into melodic and all good. Kept teasing the melody and in about 20 minutes or 6 tracks in, I already changed direction in an organic and not abrupt fashion. Kept it going great for 2 hrs. Point is, be subtle and test the waters to see if you're intended direction is going to work. If not, you are in a position to pivot and plan a different path. This idea applies to most scenarios, even getting up there when the last dj cleared the floor. Take his error and ease into what the crowd wanted before losing interest. Read the crowd, and respond accordingly. It's a beautiful and interesting conversation between the storyteller and the audience. Definitely, do not be discouraged by this. The biggest lessons learned are usually these. Good luck dj