It seems to be fairly common with the smaller breeds. Just give her lots of loves. My vet thought that Maddie was having a false pregnancy also, for about 4 weeks after her heat she was very sleepy and clingy Her breast tissue was a bit swollen still. I have read that some actually act like they are pregnant for a full term (and even carry arround little toys like pups
), her's was not that long and as soon as she seemed back to normal I had her spayed. She is doing great. I really felt bad for the though be cause it was obvious that durring that time she didn't feel very well. I am sure there will be someone that can give you more info on it, as this was my first and only exp. with a false preg.