found it very fascinating to be honest

And thank-you for this fascinating question! Here is my attempt to answer it, for both you and myself.

Since the 1940's consumer culture has taught men (and now, women thanks to feminism) that material possessions and status (job, the house, the TV, the car) would make them happy. Instead, it does not. As George Carlin joked, you're just left with a house full of stuff.

They were told what to want and how to want but not why to want.

Here's the why and it's deceptively simple, something that our ancestors knew about but somehow we has a society forgot: Legacy. How will your life improve those who come after you?

When you have children, it's easy. You leave them a better life, and teach them the what/how/why of making the lives of their children better.

My only concern is when I look back/think about it do you feel weird about dying one day, leaving your house/all material possessions behind that you worked so hard for all your life to nobody in essence?

Ey, there's the rub. But what if you have no children?

I am choosing to not have children nor marry. Instead, I am studying medicine and putting all my time and effort into that career. When I die, my Legacy (what I accumulated in life) will go towards scholarships for young people who cannot afford the schooling that I was privileged enough to receive (no, not using the SJW usage of the 'privilege') and towards funding into research into the branch of medicine I choose to pursue.

When you die make sure you leave a Legacy. Your Legacy isn't about glory, it's about the next generation.

Far too long we've been focusing on 'cradle to grave' when in reality it's 'cradle to cradle'

Good luck, OP. You sound like a good person.