I hope Alex is better soon! Pancreatitis is a nasty thing. Paxil and Preacher have both had near fatal battles with it.

Paxil has a case of mild, chronic pancreatitis. She had a bout with the disease a couple years ago that was so severe her pancreais is permanently damaged. When Paxil has a flare-up now, it's much milder, but sounds much like your boy's symptoms. I give her sub-q fluids for a few days, along with no food(if she's vomitting) or a very bland diet if she's keeping a bit down. The fluids make a world of difference for her. Easy to do and saves a trip to the vet. I take her in if I don't see improvement with the fluids after a day or two(or if she continues to vomit.) Might be worth learning how to do fluids and keeping some on hand for Alex.