My dog, a 10 lb chihuahua, woke up this morning shaking. I took him out and he had diarrhea. Not much came out. He acts sick and shakes a lot. He did throw up once on the couch and has gone diarrhea in small amounts about 4 times today. I remember last night I saw him grab a whole grape and eat it. I didn't see if he chewed it at all though. Now I'm super worried that it's stuck in him. I know grapes are harmful to dogs, I don't give them to him but he has gotten ahold of them before and never acted this way. How do I know if he's just sick and feeling under the weather or if it's something more serious.