Is My Cat stressed?

I'm having a problem with my kitty and I was hoping someone could shed some light before I take him to the vet. I recently...ie within 2 weeks...moved into a new house. I put my litter box on the 3rd floor, where we never go, however my cat has decided that my 2nd floor office is where he wants to use the bathroom...both ways. He is also losing some weight, and I was wondering if maybe he is stressed out with the move. We have actually moved twice in the past 3 months.

 

Moving house can definately cause behavioural changes, its extremely stressful for pets, I think more so for cats than dogs, maybe put the litter box where he wants it for now and then gradually move it into another room. I wouldnt let him outside yet either (if he goes outside that is), every time Ive moved its taken my cats at least a month or 2 before they settle back into a routine.

 

I have to agree with DeLaUK