I'm grappling with similar questions, and have been my entire adult life. It feels like an unending existential crisis. I think both your comment and the parent comment (which are both very thoughtful, btw) pose an interesting question: is 'happiness' a meaningful or worthwhile goal? For me, at the current moment, I think not. The notion of happiness seems almost incomprehensible to me, to be honest.

The way you've described your life reminds me of a book I've (partially) read: Mindfulness in Plain English. Even if you think Buddhism and meditation are a bunch of malarkey, the book itself is worth a read. What specifically comes to mind are parts where the author discusses why one should bother with meditation:

...you are human. And just because of the simple fact that you are human, you find yourself heir to an inherent unsatisfactoriness in life which simply will not go away. You can suppress it from your awareness for a time. You can distract yourself for hours on end, but it always comes back--usually when you least expect it. All of a sudden, seemingly out of the blue, you sit up, take stock, and realize your actual situation in life.

There you are, and you suddenly realize that you are spending your whole life just barely getting by. You keep up a good front. You manage to make ends meed somehow and look OK from the outside. But those periods of desperation, those times when you feel everything caving in on you, you keep those to yourself. You are a mess. And you know it. But you hide it beautifully. Meanwhile, way down under all that you just know there has got be some other way to live, some better way to look at the world, some way to touch life more fully...

...you suffer from the same malady that infects every human being. It is a monster in side all of us, and it has many arms: Chronic tension, lack of genuine compassion for others, including the people closest to you, feelings being blocked up, and emotional deadness. Many, many arms. None of us is entirely free from it. We may deny it. We try to suppress it. We build a whole culture around hiding from it, pretending it is not there, and distracting ourselves from it with goals and projects and status. But it never goes away. It is a constant undercurrent in every thought and every perception; a little wordless voice at the back of the head saying, "Not good enough yet"...

Maybe the Buddhists have got it right. Perhaps the more worthwhile goal is cultivating a clear and unbiased perception of reality. Honestly, I have no clue; just putting forward an alternative to consider if you haven't already. If you do figure it out, I'd love to know...

Here's a link to the book btw: http://www.budsas.org/ebud/mfneng/mind0.htm

EDIT: reading firstworldman's sibling comment provoked another thought which may head off a semantic issue. Maybe 'happiness' is neither a meaningful nor meaningless objective; it's simply an ill-defined, subjective concept. So when people talk about 'attaining happiness', its possible what they mean by 'happiness' is objectively different to what other people think it is. From what I understand firstworldman to be saying, he has found 'authenticity of experiences and relationships' to be a worthwhile and attainable goal. Incidentally, this seems to square with Buddhist philosophy, which is largely concerned with attaining 'perception of authentic reality' (i.e. 'enlightenment').