That's exactly what I was thinking--that it sounded like a panic attack. With the getting hot/flushed, upset stomach. I can have those and then a half hour later be fine and laughing. They can be really awful and scary while they're happening, then when they stop I tend to be OK. So it's possible he really was feeling awful for a bit. But I get the sense your H wouldn't be the type to admit it might be anxiety, so he tries to find a physical explanation for it.