This is cool stuff. The colors are nice. I get the concept too.
The thing is, this would've been my problem, and always has been my problem with making collages - I wouldn't want to cut up a magazine with pictures that pretty. Ugh.
So, yeah you shouldn't be so hard on yourself. There is classical style painting and drawing that takes honed skill, but collages are just one of those things you can go wild with. That's why I've always liked them.
And I've had that rookie problem too, always, of having such a wonderful vision in your head and then the scale and depth on paper doesn't want to cooperate. And that's where you get reminded just how much you suck at art, but hey, it's fun, and that's half the reason to do it. So yeah, you should make more collages 'n stuff, dogbun.