I understand you are upset and maybe this is something you could talk to you’re mum about however your parents separated for a reason they both want to be happy and maybe just didn’t feel that way around each other anymore. Your feelings are valid and you must miss your old home a lot but you should try and get used to your new life this is an issue you yourself cannot solve but try to make the best out of this situation and maybe in the future that house could be yours, you never know ;)