under the weather

under the weather (sick, not well)

under the weather (to feel ill, to not feel as healthy as one usually does) — плохо себя чувствовать

Example 1: I don't think I'm going to school to day. I'm feeling under the weather. — Не пойду я сегодня в школу. Я себя плохо чувствую.

Example 2: After I had spent the whole afternoon stranded out in the rain without a jacket, I was feeling a bit under the weather. — Весь день я проходил под дождем без куртки и потом как-то неважно себя чувствовал.