An emotion is not an object that can be lifted from the ground and thrown through the air. Nonetheless, emotions are felt by physical beings who experience the world through their bodies. People are animals with a consciousness that arises from their biological complexity, not abstract spirit beings. Our feelings take place at the confluence of subjectivity and objective reality.
So it is that we can feel up without moving our bodies at all.
We associate height with a combination of energy and optimism. We can speak of feeling elevated, as if we have risen above our surroundings.
Feeling up also carries with it a readiness to take action. No longer are we willing to take things lying down, or to sit by while events take place.
There is no need for us to rocket into the sky like Superman, of course. Feeling up can be a matter of perspective as much as of movement. It’s enough to say that things are looking up, even if we do not rise ourselves.