Yes, I've been in therapy for a few years now, and I'm on meds. I've been working very hard for many years to find an answer that actually plays out.
I struggle with whether or not my situation and history actually matters at this point. Things are what they are and there is no changing them. I try to not worry about that which I cannot control.
Statements like "happiness is a choice" perplex me. For me, it isn't. I don't have a choice in the matter. Life happens, you die, end of story. What happens in between is really of no consequence that I can find. Saying that I can make a choice and somehow make the outcome different is a fallacy that has no basis in reality.
Even without looking at the finality of it all, for me to believe would require me to know what happiness is. I don't. I can't remember a time in my life when I did. Sure, there have been times when the world is less sucky than others, but those are so fleeting that I can't classify them as happiness.