I've had times when I've felt exactly the same. And the conclusion that I've come to, and the mantra that I repeat to myself is:
"Who you are, What you do, and how you pay your bills" don't need to be the same thing. And in fact you don't want them to be.
Two out of the three is fine. But all three being the same should be avoided like the plague.
After 9/11 completely tanked my planned career in Near Eastern Classical Archaeology, I floated around for a bit. Got some IT certs, but mostly have worked a series of crappy retail management gigs. And yeah...for a long time, it bothered the fuck out of me. It didn't help that I suffered from depression. But I get that same "what's the point feeling".
But I've also written for my entire life, and I have a number of things that I'm become decent to good at over the years that I've used for passion projects. I was bored so I learned video editing and use those skills on other people's low budget projects. I have a decent level of Blender knowledge and I enjoy flight simming, so I spend a lot of time creating aircraft for X-Plane. Both of those have netted me very minor amounts of money through paypal donations, etc... But that's secondary to doing something that I love because I don't need them to pay my bills for me.
So while retail management is how I pay my bills, it's not who I am and it's not what I do. In fact I tried doing the freelance writing thing for a bit and I ended up miserable because What I do and How I pay the bills became the same thing and it stopped being fun.
Retail management pays my bills, and allows me the free-time necessary to pursue my passions in my free time.
Long story short, and I apologize if you don't find this helpful at all, but you're biggest disservice to yourself is thinking that "working at Walmart" is who you are. It's not. It's just how you pay the bills so that you can pursue your actual talents on a full belly.