Exercise releases endorphins, which make you feel good since its the bodies natural way of rewarding itself for something, which is partly why certain, ordinarily non-addictive, things become addictive to people.
Anyways, science lessons over, yeah I need to be keeping myself more active and occupied with any little thing I can find.
Also codeacademy is fucking awful, I know about KhanAcademy, I have the app, but I've barely used it
Bonus science lesson for anyone interested though. Simply just being outside is incredibly useful for fighting back depression and similar things, especially when it's fairly sunny and the weather is nice, this is mostly because the sunlight causes your skin to produce Vitamin D which is both a vitamin and a hormone, which acts in certain parts of your brain affected by depression, helping to alleviate symptoms.
TL;DR: SUNLIGHT IS GOOD FOR YOUR MENTAL HEALTH AN SHIT YEAH? THAT SHIT MAKES YOU HELLA HAPPY.