Lately my 1 year old Chihuahua, Dakota, hasn't been himself. Every morning he would be the first one to want to run outside and play, but lately i have to draghim out of his cage. Also I have noticed that he hasn't been eating, I would even try and give him his treats, but he just leaves them there. The weather has been changing as well. Also about two days ago, it seemed like he had greenish diarrhea. But since then I haven't seen anything else. I'm just worried about him, does anyone know what can be wrong? And what can I do as his mom to comfort and make him feel better?