Could my Bulldog be pregnant?

Question
My bulldog just finished her first heat cycle.  She started it exactly 9mo to the day.  I also have a male bulldog.  I was very carefull at keeping them apart during this time.  caging the female most of the time and when she wasn't caged, she was in a separate room.  Now that her heat cycle is over though her breasts seem enlarged.  Is this normal for her after her heat cycle or should I be concerned that my efforts failed?

Answer
It's highly doubtful that they could have managed a breeding on their own especially without your assistance. First heats are often extremely intense and can have after effects that resemble pregnancy for a month or so. Often a females nipples will look enlarged and stay that way. It's nothing to be concerned about. You did a good job.