Ugh, I know that feeling...
Seriously, almost everyday I make a new track, declare it's "shit" and abandon it
forever. You should see how much my hard-drive is clogged up with unfinished bit's and bob's. My opinion on my music is low. The main problem I have is I always ask myself, "Would I actually listen to this crap if it wasn't me?" 9 times out of 10, the answer is no.
The thing is though, I just have too much fun making tunes! Part of the reason I don't finish every single one is that I like to keep them for myself to play with almost like a game that never ends. I find it far more fulfilling making something that I can play with by myself (INB4 fap joke) than subjecting it to the harsh words of the scrutinizing public.
My rule is, if the fun stops, I stop.
Meh, but I'm weird. I can't really say much else that hasn't already been said already, but I'm glad to see that you're sticking with it. I think that that kind of positive attitude will most likely show off in your work, too! So good luck!
(Also, grr! I wanted to seem knowledgeable & insightful by posting that Ira Glass quote! Damn you Aussie with your knowledge and insightfulness-ssuss-uss--ssss!)