Ball pythons will go off feed for months, and you don't have to feed him anything thats going to be hard to get or $$. Feed him with what he ate before. your big mistake is moving him back. if the conditions were right at your girlfriends you should of left him there. Now by moving him back it did nothing but added more stress. Put him where you want him to be with proper temps and humidity. Don't wait until he starts eating if he needs to be in something larger, move him now and leave him be to settle in, then offer food to him every week or two and he will eat when he's ready. I remember when my first ball went off feed for the first time and it was months, I started freaking out too. Good Luck don