I don't know why you would feel that way, your art looks great.

There are always things that can be improved on, you know that as an artist. Taking requests can help at least, considering sometimes the request can be outside of your comfort zone and it's a learning experience. Plus it's not something you will get paid for, so there's not "too much" pressure going into that. If you don't feel confident though it's good to at least take some requests anyways as practice under your belt. Other than that just have some tracing paper handy and pictures of models, and deconstruct the form and draw from life. That's always important.

Its hard to draw when you have depression.

I do suffer from mild depression so I know how that feels.

No one is perfect, not even Bernal with his furry art.. You have a nice style that is your own and ultimately YOU should be the one happy... unless you're being paid :P but Yeah, don't be so hard on yourself, you're among the better artists I've seen.

the people pointing out flaws probably can't even draw a stick figure.
don't let them get to you.
you have your own art style..your own voice..just keep rockin it..stop trying to be somebody else's perfect.

couldn't have said it better. Just keep on at it.