A lot of writers quit at this point, because they LOVE that novel, they put SO MUCH work into it, and they just don't think they could do it all over again.
I'm thinking about that right now. Not that my current query round has failed -- it hasn't by a long, long shot -- but after 100+ rejections on two previous novels, even a single form letter can make me wonder if I'll ever get past this stage.
So here's what I do (in order of increasing surety of failure):
- Take another step. If you got a rejection, send out another query. Another month of slow self-pubbed sales? Hit up some book bloggers, write some guest posts. Basically, as long as there's something you can do about it, get up and do it.
- Remind yourself what's good about the novel. Find the critiques where people told you how much they loved the humor or the dialog, or the comments on your query that said, "I would request this." Remind yourself that you DIDN'T write crap. You just haven't found the right agent/readers yet.
- Make a new plan. You love that novel a lot, right? So how can you revise it to be even stronger? What critiques did you ignore before that now, maybe, look like something you could do? Revise that novel you love so much, then try again.
- Find a new story you love. Maybe there are no more steps you can take. No more agents, no more revisions. That novel is done. This is hard to accept, but the best way through it is to find a new idea that you can love even more than the first. Believe it or not, you DO have more than one story in you. Everyone does.
- Take a break. Feel you have no more ideas, or the ideas you have just aren't big enough? Take a break. Remind yourself why you love your life, and why writing is NOT your life. If writing really is your passion, then the ideas will come, but don't worry about that right now. And don't write the first idea that comes knocking either. Give them time. Let them grow into something HUGE, and enjoy your life in the meantime.