Being happy is a matter of personal choice, so if you wanted to be happy you will no matter what were the circumstances, so for an example if you wake up and started convincing yourself that you're sad eventually you'll be really depressed, and the other way around so if you convinced yourself that you're happy you will be a lot happier and you'll notice the difference, but from the other hand you cant always be happy, but the trick is to find the happy (bright) side in your unhappiness, sometimes I actually try to convince myself that life is a game, and it'll be very boring if it didn't have any problems to make you feel sad, and once i actually think about it I start feeling better and better until I forget the problem completely, so this is a very good trick to try, another thing you can do is to share your problems with someone you trust, and ask about his opinion about, this trick helps very much and you'll start forgetting about your problems in no time, another great trick is to always think that you're not the only one in this world that has this problem, and if you can find someone within reach that has your same problem talk to him about your shared problems and you'll see that the impact of this problem on you will start fade slowly until it disappears , so at last I just wanna say that being happy is only a matter of personal preference.

Thank you