It's great when you feel happy, and people often can take it for granted, not truly appreciating the way that they are feeling.
We want everyones happiness to last as long as possible, as life's too short to not be, and to do so we need to truly understand our feelings.
When you feel better, try to think about what it is that made you feel better. Did you spend time with friends or family? Submit an assignment? Got a new job?
The point is to savour these moments, and try to continue doing things that excite us and that we enjoy.
Going forward, try and stay positive.
Keep doing things that make you happy, try new experiences to test yourself, and most importantly, try to share you happiness with others.
Sometimes something very simple is enough to make someones day. Try to think about how you would feel if someone went out of their way for you, and reflect this in your actions.