I was about that age when I had a similar experience. I was working in fast food and teasing my manager about his age, when he countered "Don't laugh, you're on the downside to 30."
I started to say something clever, but before I could get it out, I realized he was right. I was 26 years old and working in fast food. My entire life was ... a game. I had done nothing.
I suddenly felt - really felt
that expression "life is passing me by". And it was, everyone else was getting on the train of life, getting jobs, getting married, having kids. And here I was just standing there on the side of the tracks.
I know you don't feel like you can leave, J. But, I really think a change of scenery will do you good.