There's not much use in feeling bad about it. All creatives (or at least, every one I've gotten to know) run into dissatisfaction with their work. If such a thing happens, it's fine to wait until a better time or ask for help, or even if the finished product is still unsatisfactory, try to learn from it for next time. Focusing on what's bad versus what good can be made of it will probably only make the feeling worse.