Awwww it is always a big event for a cat to change houses and some do really get upset.
I always keep them inside the first six weeks so they get to know the house and it smells good.
Then I go in the garden with them and bit by bit the get more space, just to be sure they don't wander of and get lost.

In a few weeks your sweet cat will be used to the new house and happy again :)

Happy Caturday !