Thanks Elysium and Lynn, I appreciate your replies

My dad dropped my sister home and as soon as my dad arrived, my dog was acting a little bit more himself (he absolutely loves his grandpa!), and my dad checked him out and said it looks like he might have some joint pain because we noticed then that he was sort of limping a tiny bit with one of his back legs. The vet told me before (when he used to get growing pains from 'panno' which is common in german shepherd puppies, to give him buffered aspirin which is supposed to be safe for dogs to take). He seemed a little better after taking it but still is not himself, so I think I'm going to call the vet tomorrow and take him in if he's still not better. If he gets worse tonight though, I won't hesitate for a second to bring him to the emergency vet. I will keep you guys updated on how he's doing.. thanks again for your support and positive vibes for him.. it's amazing how much love a dog can bring to a person. .I don't have any kids so to me, he is like my child. I just want him to feel better and be his playful energetic self again