Kiddo had both fluid and blockage. Both were related to the surgery and not a stomach bug. (I suppose there's still the possibility there was a stomach bug - there's no positive evidence that rules out the presence of a virus - but surgery complications is an adequate explanation.)
They drained the fluid. Daddy got to watch! They're in the process of loosening up and flushing out the blockage.
His belly has an infection, so they're going to keep him in the hospital for at least one more night, probably more. I'm taking the bus and trading places with Daddy. And I have to leave very soon because my ride to the bus station is actually a friend who will be on her way to church.
Bussing it on Easter Sunday. Yay. Save some ham and chocolate for me, everyone. (Chocolate, anyway. I'm not much of a meat lover. I'd actually rather have some Easter eggplant parm than ham.)
(I'm not mad at the pediatrician. I see what she was trying to do. She thought an X-ray was unnecessary and wanted to spare him the ordeal. As luck would have it, her diagnosis was wrong. And yes, there is some wisdom in the idea that if the kid just had surgery, you should check for blockages just in case. In hindsight, I should have subscribed to that line of thinking. I should have asked her for an X-ray anyway. But I saw her point and hoped she was right, and it turned out she was wrong. Sorry.)