Let's stop and think about this for a minute.
What does UNDER the weather really mean?
Sure, it is supposed to mean that you are not feeling so hot.
You are sick.
But, aren't all of us always under the weather?
The weather is above us all and falls to the earth.
Sun and clouds are above us.
Rain and snow comes from above.
So, we are all UNDER the weather.
All the time.
Unless, we are in an airplane flying above the clouds and storms.
Or, in a spaceship in another galaxy.
At that point, we would be above the weather.