I've noticed that sometimes Zoe will do this odd gagging noise, like a really squeaky cough. She only gags once, then she does her thing. Nothing comes out, but I've noticed that she only does this within about 3 minutes after she was cleaning herself. Does this incline towards a hairball? We've had no problems yet... I'm not too worried, but it does spook me when it happens all of a sudden. Is this normal?