I was still feeling a bit under the weather.

我依然感觉有些不适。

《柯林斯英汉双解大词典》

For example, under the weather is an idiom meaning ill. So when people say "I'm under the weather", they are saying that they're not feeling well.

例如，“under the weather” 这个习语的意思是“生病了”。所以当人们说 “I'm under the weather” 时，他们是在说他们感觉不舒服。

youdao

Brian: Yeah. I've been feeling under the weather recently.

布莱恩：是啊，我最近病了。

youdao

If you plant the seeds outside when the weather is cool, place the seeds under a glass.

VOA: special.2009.04.21

Even though several days of cold, wind and rain gave way to warmer spring temperatures at Phillip Island, the Spaniard was feeling under the weather, struggling to the sixth fastest lap time.

BBC: Matt Roberts' MotoGP column

This year, the 36-year-old Academy Award winner played the title role in the TV miniseries "Mildred Pierce" and an infectious-disease expert in the film "Contagion" (where again, she appeared a little under the weather).

WSJ: Kate Winslet On Playing One of Four Caged Animals in Carnage

And now Martin is under the weather, too.

WSJ: Knicks try to recover from illness, offensive woes