This card, actually came up reversed when I pulled it. Because it is an Oracle card, I usually see those as heightened in their importance when pulled reversed.
Cheer Up is telling us to stop living in the past, and forecasting the future. It is begging us to shift our focus from what is bothering us, the argument, the pain, the stress or worry… and focus on something lighter. It could be as simple as petting your cat, or making a pot of coffee, or listening to your favorite song. Do something to help yourself pull away from whatever has you upset and shift the energy. Go for a drive, bake cookies, look at old photos! Live in the moment and enjoy what you are doing. Right now, me writing this post helps me lift some of my own heaviness and enjoy being in the moment.
If your heaviness is exhausting you then take a break. Listen to some gentle music and doze off for a while, or curl up in bed and relax.
It doesn’t have to be a huge grand gesture, but taking little steps by doing small things that you love, will help your spirit lift and cheer you up.