It's only been a couple of days? I don't think there is anything to worry about yet- too soon. Give it a few more, and if there is still a problem, call the vet.

About 4 years ago, when my husband and I moved, it took one of my cats a FEW WEEKS to adjust. For the first few days he did not eat or use the litter box. He did eventually when he got hungry enough.
He was upset though for a good 3-4 weeks, and two times did his duties on the bed instead of the box (Natures Miracle works awesome!)

It will all work out eventually, I am sure!
Good Luck