There's a yin and yang to life. Sometimes you're happy, sometimes sad. The summer is hot, the winter is cold. One year it floods, the other brings a drought. To every action there is an equal and opposite reaction.
I know this might seem clichéd and basic, but typically... most of the time... if you're patient... things even out.
That balance is as much a part of the natural order of things as it is a part of your mindset. In the middle of the yin of a depressing time it's hard to imagine that the yang of happiness exists, but if you can take one moment to realize that this too will pass, that's the one moment of hope that will set you on the path towards joy again.
Expecting balance is one thing you can do to stay present. Pursuing balance directly is another way to help get you there.
You get to determine the path you will take every day. You get to choose whether or not your life has balance.
There are three paths... you could give into all of your desires and eat fried chicken, cheeseburgers, and poutine every day. You could also torture yourself eating only quinoa, kale, and tofu. OR you could strike a balance, learning to enjoy fresh vegetables for all their benefits while also allowing yourself to enjoy life and indulge in a gravy soaked french fry once in a while.
Three paths... you could spend all day updating, commenting, liking, favoriting, and reading articles on Facebook and Twitter. You could also cut yourself off from the world, ignoring messages from friends and the day's news. OR you could strike a balance, using social media to connect and engage but then turning it off when it becomes a distraction and it's time to get work done.
Yin and yang. Life in balance. Everything in moderation.
When you decide to strike a balance, when you make a conscious effort to enjoy both sides of life without overdoing either, that balance slowly becomes the norm. The extremes of your life that caused guilt and anxiety are washed away by your new, even, easygoing, balanced mindset.