Why am I upset my parent are getting back together?

My parents have been split up for around 8 weeks and at first was really upset and just couldn't stop crying but maybe 2 weeks ago I realised how much calmer things were and I started to look on the bright side of my parents splitting up like I started having a better relationship with both my parents even though I haven't seen my dad as much the time that we have spent together has been really nice and special and me and my mom have grown closer.This morning my mom told me that they were getting back together and that he was moving back in next weekend, then a few hours later I found thEm booking a two week family vacation even though the last few times they have spoken to each other they have ended up fighting so I am really confused but thought I would be really happy to find out that were getting back together but I'm not so I was just wondering if something similar has happened to anyone else or knows why I feel upset about it.