No matter what you're currently experiencing, remember: you set your mood, not your circumstances.
It's a well-known cliche that what happens to you is 10% events and 90% how you react to it. A cliche because there is a nugget of truth there.
Of course, if something awful happens, you can reasonably be expected to be sad, angry or disgusted. No one wants to lose a pet that has become a member of the family, lose their job or experience family acrimony. But life really is determined by how you choose to respond to these negative (and positive) events.
You want to decide within yourself that no matter what happens, you're going to be happy anyway. You want to reassure yourself that you can handle anything that comes your way. You want to acknowledge that worry is fairly useless because you have absolutely no control over most things that are going to happen to you. But you can control yourself.
You can control your mood, your temperament and the quality of your day-to-day experiences. How? By deciding it's not worth staying angry, distraught, sad or stressed out every single day. By deciding to allow the good experiences to stay with you longer than the bad. By deciding to meet life's challenges with a good deal of determination and the best attitude you can summon. And if you need more inspiration, remember that you are not only hurting yourself, but affecting the ones closest to you as well. So calibrate your attitude and set it at its highest level.
You can do it!
Remember - it's not your circumstances that set your mood.
You alone have that power.