why am i not happy?

I'm a girl who pretty much has everything. There's nothing much that I'm deprived of really. Nothing except absolute freedom. I guess even then it's more because of my personal sense of responsibility, that I perceive myself to lack such freedom. If I really want to leave and pursue something entirely different from what I'm currently doing, no one can really stop me. Technically that is the case. But in truth, there's more than one thing holding me back. Or perhaps I just lack courage. Cowardice. Maybe that's it. But will leaving really solve my problems? Especially when I don't even know where the problem lies, or what the problem is. Maybe there's not even a problem; and it's just me being all melancholy over nothing. I don't know. All I know is that I've been happier. Much happier. And I want to get back to that you know. To be my usual happy self. But how? How do I get back to that point of satisfaction, where my life is in perfect equilibrium? I hate my melancholy self. And I know it won't last, for it's not the first time I feel this way. It comes to haunt me once in a while, ruining my moments of happiness. Hate the joy that's like this. For this is not inherently me. Give me back my mirth.