How to keep oneself happy to not think of the stress we are facing?

It really depends on what is the stress and source of stress that u are facing - stress is a v big word. If it is not something too dire, I would suggest me-time, do some things that u like, have ur fav food/drink. If it's something that can be solved u can brain storm about it. U can also go for sports or dark chocolate which will release endorphins into ur system to give u the "feel good" feeling