rapid breathing toddler

My 18 month old is currently asleep and her breathing is a little more rapid and loud than normal and she wakes for a few seconds and goes back to sleep. It sounds like she has a slight stuffy nose but would that explain why shes breathing alightly faster? She has seemed fine all day. Could she just be getting sick? Im scared to even take my eyes off her or leave the room incase somethings really wrong. If it keeps up ill be taking her in to be sure but just want opinions?