Insecure Writers' Support Group to this post last night. Now I'm officially signed up!
As a working parent, I already have a lot of day-to-day tasks to juggle, along with occasional (well, maybe not so occasional) mini-crises and long-term worries about what the world will be like when my son is of age and I'm a crotchety geezerette. One thing I don't want to worry about, however, is my writing.
Reading and writing books is my escape from my ordinary world, my personal time. Writing can be draining, especially if you're sacrificing sleep to fit it in, but it also provides spiritual sustenance you can't always get from daily life. It should be a source of pleasure, even joy and accomplishment and control, not a source of worry or other negative feelings.
This doesn't mean that I'm free of worry when it comes to writing or my writing career. When I'm unable to write and am in the middle of some mindless task, I might wonder if I should do something different with my work-in-progess. I might worry if I'll ever be prolific or popular enough to make a decent living from my work. But I have to ignore those concerns when it's time to write. I need to get inside the mind of my current POV character, and I can't do that if I give him or her my own problems. I don't have a specific technique for doing this, but I think training myself to write at certain times of the day helps put me in the right mindset.
No matter where you are on your writing journey, you will always find something to worry about--if you focus on that. Focus instead on your story and the joy of sharing it with the world. You can always worry about revisions or marketing when you reach the right stage of your work.
Now if you'll excuse me, it's past time for me to write.