my dog just started randomly flinching about 2 hours ago he is fine when he i relaxed but as soon as he gets exited it starts again he is normally very hyper but seems very depressed now he is not eating all of his treats so is dropping them. he is a 2 and a half year old rottie and he has never behaved in this way before he is like a whole different dog also he has begun to dribble a lot more than normal .