Well, it's been a long time since mine was 5; but I do remember that he was very much "in our face" every waking moment. I asked my doctor about it and after he explained it to me, it all made sense.
When our little ones graduate from mommy's hip, and they become mobile - they feel like they are invincible and can do anything because "their big kids now".....well, that is unless you get out of their eyesight....and then they get their "freak on" (smile). Remember my friend, it is a short phase.....and believe me it won't be long and you'll be wishing for those precious days back. They leave our arms and never our hearts. She'll do just fine mommy, she may very well be picking up on "something"...and that's a good sign. Children are the most unfiltered human-beings on the planet; they have the closest thing to God's heart and can sense all kind of emotions.
Don't worry about it (just my opinion though); savor these wonderful "cling on moments"......because they will end much sooner than you're ready to let go of.
"I believe that friends are quiet angels who lift us to our feet when our wings have trouble remembering how to fly." - unknown