Anyone ever feel that something is holding you back from reaching your full potential, but you can't quite put your finger on what it is?

I'm 23, work a good job, I'm in great condition, and at average graduate student stuff. But I feel like there's this huge blockage between me and my true capacity. I've always been a bit of a perfectionist, and I can't help shake this feeling that I'm wasting time, even if I spend all my time studying, or working out, or learning. The feeling isn't extreme, but it's there. I'm not like Dumbo with the feather, I don't think it's in my head. Anyone sometimes feel like this, or is it just me?