I probably had these feelings more so when I was younger, but usually about writing. I often loved to write stories or short fiction and sometimes would find, after labouring over a piece for weeks, that I'd love it. Then come back to it later and think, "This is wretched!" and want to burn it, in fact sometimes I did burn my writing. Oh the drama of the creative, correct?

For me, though, with art it is often different. Of course I have hated things I've made but I sort of came to a zen place awhile back that said to me, when I come upon that feeling with a piece I've made, I've just got to put it away and immideately do another thing. Sometimes, it has spurred me onto just start a new piece and get engrossed enough to finish a larger piece in one day. So, I try to take the negative and turn it into a positive energy, almost a way to say to that feeling, "Nice try! I'm not letting you win, I'll be happy with something by the end of this day" and overall it worked. In a way it was like forming a new habit.

Now that I art everyday, part of that is to have a 'finished' piece each day, this often means just a sketch or maybe with a splash of watercolour, real or digital. But, I call it done. It might become (and often does) a study for a larger more involved piece, but I still give it that label of 'finished' to myself. It has a power to it. It makes you feel like if you do dislike something you can simply move on and then that negative feeling doesn't get a chance to take hold.

Good luck combatting it. We all deal with things differently but I think even chatting about it on here is helpful. I love your work, as do many others, so if you feel down just think, "I'll do it for the others who do appreciate my effort, even if I feel I am not". :)