With the self-loathing, I feel personally it's all in ones head. This doesn't exclude me form feeling this, as I feel it at a constant. Believe it or not, I live for someone to tell me my work doesn't suck. But something I've learned is that we judge ourselves more harshly, then others do. And maybe sucking is sometimes needed. I see a lot of my stories, I wrote when I first posted, and think, this is complete and utterly shit. And in a sense it is. Having self-loathing (In my opinion) is a way to improve. You see what you've done and you say, "Oh this sucks." And so you go back and pick out what's wrong and improve. Simply saying it's crap and walking away gives it no use. There isn't much more I can say that makes me even sound remotely original, considering,
@Keleri said, is pretty much true.
But as an extra point, don't think of any self-loathing as something that gets in the way. I see it as you telling yourself you need to improve. It's your drive to improve, because as the cliche says (which is extremely true), "There is always room to improve."