Cats can sometimes take awhile to adjust to a new environment.  From stressing out and getting runny eyes and nose to acting out of their character.  Whether this is an only cat or if they have new buddies every cat reacts differently.  In the link below are some tips and useful information to help or curb behavioral issues. 

http://www.hsus.org/pets/pet_care/our_pets_for_life_program/cat_behavior_tip_sheets/