Pancreas levels are high?

Pedro, my little 9 year old chihuahua had been acting weird last week. Fireworks had been going off.. and he's scared to death of everything, so I honestly just assumed he was frightened. Well he had stopped eating all together so we called the vet first thing on Friday. My mom took him because I had to work, but they are keeping him until Monday at least. Bloodwork showed his pancreas levels are high. He had a slight fever too, but hadn't vomited or had diarrhea and wasn't dehydrated.. which is a good sign. They said they are going to put im on an IV.

When I had his teeth cleaned on Feb. 20th, I paid extra to have bloodwork done ..that was suppose to check all of his organs as well. I am now wondering if they didn't do those tests.. or can this type of thing happen in as little as 3 months? I have been trying to read up on it.. fatty-foods can cause it. He doesn't really get table food, and on the rare occasion he does.. it's usually tiny pieces of baked/grilled meat. Nothing greasy or really fatty. The one bad thing he eats are those pup-peroni sticks.. which I didn't even think of until now. He eats Natural Balance food. He's not overweight.. I know his age can play a part in it. But surely it can't be caused by his prescripton anxiety pills Diazepam (only taken when stressed) ..he's only taken it twice.