We hope that you are taking in all these fantastic idioms to add to your arsenal.
This one is definitely something you can probably use quite a bit in the winter season.
"Under the weather "
This means that you are feeling sick, but not so serious.
A. Why didn't you go to the movies with us last night?
B. Sorry about that. I was under the weather. I went to bed at 8 o'clock.
A. Are you feeling under the weather? You don't look so well.
B. Yes, I think I caught a slight cold. I'm going home early tonight.