You might find some of Need/Want's blog posts useful: http://needwant.com/blog/

They also did an AMA awhile back on DN: https://www.designernews.co/stories/54884-ama-marshall-jon-david--cofounders-of-needwant

I always dug The Players' Tribune. Scroll up and down to see it animate.

I don't use this enough, but I always thought it was useful: http://www.materialpalette.com/

Think of it as a good thing. You've got good taste - one of the intangibles of becoming a good designer. Because of that, you feel like your designs are never adequate, or just short of being there. There came a point in my design career that things just started to click and I was happy with what I was producing. Perhaps it was because I'd reached somewhere around my 10,000 hours.

I love to share this video with fellow designers to show that what you're experiencing is completely normal:

Ira Glass - The Gap https://vimeo.com/85040589