i've actually heard that just pretending to feel happier can trick your brain into thinkin you are happier...but i dunno about all that...moving around a bit does help because exercise creates endorphins so maybe a quick bit of crazy dancin if possible???
Sugar and caffiene can give you energy temporarily...it depends on how long you need to act all bubbly. Listening to upbeat music can help you feel a little more bubble and energetic as well...good techno always make me wake up and want to dance.
i wonder that every day, and get even more depressed. it all depends on how you slept the night before I believe. If you have lots of stress or anxiety it will drain your brain and body.
Why would you want to pretend something you're not feeling? I guess try to make yourself feel better and the bubbly will come. Do something you enjoy doing.
take everything slow; sit down alot and relax