DDog does this thing when he's sleeping where he will start breathing very fast for a short period. i thought nothing of it, put it down to dreams but just now he was sleeping and i had my feet resting on him (he's big) and he started the really fast breathing but his heart started beating really fast too. it only lasted for about 10-15 seconds and then settled when the breathing slowed again but was a bit irregular. is that normal or should i get him checked out? otherwise he seems perfectly healthy and he's only 2.