I quit my job to become a freelance writer in 2011 too! But I did learn and improve over the past ten years. I can see how I've improved when I look at my early pieces - they were still fine for publication but I have improved. Also, when my stuff was published in magazines, I'd look at how the editors had changed things, and if they'd changed things for the better, I'd learn from that. It's a shame you didn't have the same experience. But nice that you're getting lots of feedback now!