"My stomach did a somersault"
Does this expressions mean that you are nervous or sick?

For example:

My stomach did a somersault when my boss came in. (nervous)
My stomach did a somersault on that roller coaster. (sick)

Question

"My stomach did a somersault"
Does this expressions mean that you are nervous or sick?

For example:

My stomach did a somersault when my boss came in. (nervous)
My stomach did a somersault on that roller coaster. (sick)

Answer

Usually that expression is used to mean that someone is nervous. Although I think it could work in either context. For instance, in the roller coaster example it could be assumed that the roller coaster was a thrilling or nerve-wracking experience.