I've been slogging through a bout of the "my writing sucks" blues this week. Yesterday I held my little pity party, but today, guess what? I sent out four queries.
Even experienced writers have moments of doubt about their work. The important thing is to persevere through that until the words come again without effort. If you want it bad enough, it will happen. Wanting it bad enough may mean years of hard work at your craft, but if that's what it takes to see your books in print, it's worth it, right?
Don't give up. Send out queries. Write something. Write anything. Just keep doing it. :)