funny feeling of butterflies

[keannu]

Does this refer to "ill/sick" or "weird"? Maybe the both meanings wouldn't be so much different from each other.

4)...for some people, cortisol shuts down the stomach, producing the funny feeling of butterflies. For others, cortisol speeds up the way the stomach works, which makes these people feel sick...

 

[probus]

"Butterflies in the stomach" means the feeling of nausea, that is the need to vomit.

 

[Raymott]

It also includes, or means primarily, the gurgles, rumbling or peristalsis. I don't think I've ever experienced "butterflies", but I've always assumed it's supposed to feel like your stomach is full of butterflies, which probably would cause nausea as well. Increased gut peristalsis is a common result of anxiety.
Also see Butterflies in the stomach - Wikipedia, the free encyclopedia

"Funny" here means strange.

 

[SoothingDave]

You can also get butterflies in the stomach if you are anxious or nervous, like a performer right before taking the stage might feel. Or a kid called before the school principal.