To take charge of your happiness you first have to stop letting other people and external sources control how you’re feeling- your happiness comes from within.
Take responsibility for what happens in your life. Your choices have led you to the current situation, and whilst you can’t change where you now find yourself, you can choose how to respond.
Always search for the silver linings. Figure out how you can improve your situation, or what lesson you can take from it, and in this way you can turn challenges into an opportunity for growth.