“Inspiration is wonderful when it happens, but the writer must develop an approach for the rest of the time…the wait is simply too long.” ~Leonard S. Bernstein

I write in mountains. Don't you?
Inspiration is the great provider to us lowly writers. Prometheus, if you will. The problem is that inspiration is never a constant. While months and years may go in its passionate embrace, there will be those days–inevitable and infuriating–where inspiration withdraws into the shadows, to leave us cold and alone.
The question this leaves us to face is thus: do we press on without it, or wait for its return?
Some people wait. Personally, I’ve always found it silly. Growth happens regardless of whether or not you’re “in the zone,” and I daresay that if you find yourself, in that lonely forward push, stumbling through the writing, that as frustrating as it may be, it’s good for you. Failure reminds us we’re human. It also pushes us more forcefully toward self-improvement, in a way that success–or the appearance of success–never could.
Writing, as any skill, must be honed through constant practice. If we start taking large swathes of time off simply because we don’t “quite feel it,” we have the temptation to get lazy, and the writing itself could suffer. Do you want sloppy prose to be what you greet inspiration’s return with? Seems like a terrible welcome to me. Besides, there is the fact that inspiration could actually be summoned by your writing, rather than needing your writing to be summoned by inspiration. Immersing yourself in the world, in the characters, in the poem, what have you, could draw back inspiration as quickly as anything.
The other side of this, of course, is that if you don’t get a part just right, if you press through the numb of non-inspiration and end with a few thousand words that don’t quite capture the personality you know it needs, you’re not doing yourself justice. That is the beauty of writing: editing is a key part of the process. If you’re not going back and re-reading yourself anyway, you’re doing it wrong. When inspiration comes knocking again, return to any points you were concerned about, look over it with that newly stirred creative eye, and adjust accordingly. It’s not hard.
And don’t tell me “the moment is lost” if you must go back and do that. How many edits do you make at the end of a product your creative spirit told you was gold in the first place? Your editor?
Just write. Outline. Create something. Writing is not a one shot game. It’s many layers of writing and rewriting, editing and editing again. Breathe. Everything will be okay.