I was catless for nearly two weeks over the holidays, and it took several days to get used to sleeping without my two fuzzballs. (When I got back, it was another few days before I got used to them again. Melly, you see, likes to surprise me at 3am by using my face as a pillow so that I wake up, slightly suffocated, with a face full of floof. It takes a bit to re-adjust to that.)
Do your cats sleep with you? Do they have favorite spots on your bed?