While I'm surely projecting on to OP, I think it is very common for very career or goal-focused folks to have good but perhaps not overwhelming success, then hit their mid-40s and think "Umm, what do I do now?" This can be especially common for folks that perhaps sacrificed some of their personal relationships in pursuit of their goals.
I was very lucky in that I had a fantastic therapist who really helped me understand the roots of my depression. Even then, though, after a while insight can only go so far. It's very clear to me that I've neglected nurturing my friendships and relationships, and I think there are likely others out there in a similar predicament, especially on a place like HN. I've actually started to search for a life coach that can really assist with the tactical side of nurturing friendships. That was a big missing piece from my therapy, which was otherwise great.
On one hand it's kind of embarrassing to feel like I need to pay someone to say "Yes, it's been a while, you should call Jane", and "Did you mail your Christmas cards?", and "Did you send a thank you note to Bob?", and "Why don't you invite the Jones over for dinner?", but I've come to see it like a personal trainer. Most people know the basics of working out, but they need to pay someone to actually get them to exercise. On the friendship topic, for some folks this sort of "social knowledge" comes naturally - I've come to easily accept it's not natural for me and I need some assistance.
As far as I've seen from studies of happiness, basically it all comes down to "love", it all its different forms. Modern society makes it much more difficult to build a true sense of community and friendships. I think we all just need to spend the effort to find it without some of the "default" structures that used to exist in the past.
This is pretty much what Nietzsche was getting at in his often misunderstood quote about 'God is dead', which is actually part of a larger 'Parable of the Madman' - see here if you've never read it, it's pretty insightful IMO: http://www.historyguide.org/europe/madman.html
Do you have any religious affinity, @0414throwaway? What's your story there?
Does JP have a solid answer? Not that I've seen, though the last thing I saw was a year ago now, https://www.youtube.com/watch?v=2rAqVmZwqZM. Other JP has a pretty good answer IMO. ;)
What is meaningful ...to you?
The meaning of life is to simply be happy, but we cannot be happy when others are so unhappy, therefore we must live our lives for others' happiness. Every act of compassionate service to those around us causes an upwelling of happiness within our hearts. Only by living in a service-oriented society where we look after each other compassionately can we hope to find peace and happiness.
This world teaches us that selfish greed with a callous, willful ignorance of the suffering of others, is the goal of life, but that will always -- I mean always -- lead to a miserable, empty life, especially in this world full of woe.
The journey of religion is to go within one's self and seek God's Will for our lives, to ask in humility to become an agent of others' happiness. Then you will be guided to the path that will take you there. Ask every day and every night and be thankful for what you have such that you become a kind, generous person.
And remember that that selfish, ignorant Peterson guy perverted the teachings of religion for his own selfish enrichment and power, and that he has no peace (not without benzos that is). You don't want that fate. We must cultivate our compassion and sense of worldwide community. It is not only essential for our species' survival (via global warming and the brutal fascists all over the Earth), but for our own personal happiness and peace.
"The Way goes in." --Rumi
It is definitely possible to be a wise, insightful, compassionate and moral human being without religion.
We need meaning in live. And for a long time religion gave that. But we threw that out. We now try to get "profesional therapy help". But it hardly has any scientific backing, and no one but religion has been able (even though it fails often) been offer te give any deeper answer to the question to "whats the meaning of it all".
The best solutions people like Robbins or J. Peterson offer are: just keep running so you don't think about it.