Most of the time 'writer's block' is used to describe three days of not-writing, a week of the inability to compose or edit a piece of work. Someone will wail, "I haven't written a WORD in four weeks" even though that morning they actually finished two poems.
Somebody will suggest emergency measures, such as journaling (more about that in a minute), or reading other people's work, or free writing. something. Anything. go for a walk, someone says. Take the day off, is another good one. None of this works, because if you leave it alone and don't pick at it, it will come back in a week or two, or six. If you get scared and sweaty and start free writing and 'exposing yourself to good influences", it will come back in a week or two, or six, and the free writing gets the credit.
Often the person who is experiencing this earth shattering event has just finished a series of poems, or a spate of work, or has spent the last few weeks revising and submitting work all over God's earth. No wonder they're not writing. At some point the body and the brain have to stop producing, have to stop running so hard, and take some time off. The writer's brain can only do so much for so long, and then it stops. Enough, already. I'm leaving for awhile.
Most writers have cycles of writing; one writer will write like mad for a year and then stop for a year, to recover. Another will write on a steady ongoing basis, for two years, and then nothing for six months. Regular as clockwork. The secret to all of this is to find your rhythm, and work inside it. Mine is what I call a Cicadian rhythm--17 year cycles, like the cicada--five years of intense writing followed by 12 years of blank paper. it has happened this way three times, now, and the next time any heavy work happens will be in about ten years, give or take.
No, I don't like it. So I read, and make quilts, rediscover the dust floating merrily under the bed, spend quality time with a camera and a garden. It will come back, by itself, like the cat who just wanted to stay out all night, and will come in when he's damn good and ready.
Journaling: for some people, this works fine. Every day you write bits in your journal--remembered conversations, ideas, first lines. This is perfect for prose writers, who have a fund of ideas and never enough time to implement them. But the danger is, you spend all that time writing down the synopsis of a short story, or a poem, and once you've done that, you've written the piece down, and some part of your brain wants to go on to something new. For me, as soon as the idea hits the paper, I need to extend it, work on it, finish it, AS a real draft, not just a page in a journal. the most terrifying words I can hear from another writer are, 'let me tell you about this great poem I want to write..." and I flee, simply flee. no no, I say, don't tell me. Write it down, but dont tell anyone. It has been said that Hemingway wrote some of his best short stories on a bar stool-- instead of channeling that language onto the page, he used it up by telling people. Poof, gone. The impetus to write is over.