I really resonate with your words. Life can be really tough sometimes, if not all of the time, and I just have to wonder if it is worth it. The "fake happiness" is so real, tho. I smile because I don't want my loved ones to worry, but they worry anyways because I spend most of my time in my room. It's exhausting to pretend to be okay in front of them, though, so I avoid them to make sure that they don't see through my facade when it gets too difficult to maintain.
I know that this might seem hypocritical, since I haven't opened up to those who know me personally either, but maybe you could talk to a family member or friend about the way that you are feeling? If you don't feel comfortable doing that, or don't think that it is a viable solution, know that we are here for you and ready to listen
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