Many Spanish people say something like this: "I don't feel very well, I think I am incubating". As I am sure you have guessed, this is complete Spanglish. We do you use the word "incubator". A native person might use the word "incubator" to describe the machine that is used when a baby is premature or in a different context it can be used to describe a building where there are a variety of new businesses are given extra help to grow and create employment: "a business incubator".
If you are ill and you think that you have a cold or at least you have the early signs of a cold then you can say: "I think I have a cold" or "I feel under the weather!" or "I think I am going to be ill".
Hope that helps!
Soy el director de Daniel Smith + Partners. Tengo más de 10 años de experiencia enseñando inglés a españoles.