hi Alaina, as you know bulldogs are of the brachycephalic breed so their breathing can become more labored in certain situations. Was she playing hard before her nap, or was the weather hot/warm? Just watch her to make sure she is not showing distress. I think it's not an uncommon thing. Mine do that occasionally too. Also, I understand that puppies tend to breath more rapidly and this should lessen as she gets older.
to EBN alaina21! I'm Henny 
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