Your Patronus

Your patronus but it never leaves, it always stays by your side since you first casted it even when you aren't happy. You have to find out why it never disappears (It doesn't have to be a stag). (you can cast other spells even when this one is active) You are at any wizarding school (You learned this spell in beginning of fith or sixth yr and its been with you for a month). Have fun!