Writing drought and other misterous conditions

Since the beginning of April I have been struggling to write. At first, I though I was just tired - there were good reasons to feel so - February and March were very intensive with revisions and rewritings for my OCD book, research and attempts to get a first chapter and a synopsis finished on time for Great Beginnings contest, Alzheimer blogging competition, an online course to learn to write better synopsis, writing for this and the other blog, tweeting, and on the top of that big decisions to be made in my day job.

I thought: I need holidays. So I went to South Island. I had nice time, but came back disappointed with Fiordland. It was well below what I expected to see. Maybe except for Queenstown, which pleasantly surprised my with its autumn colours and almost European feel. This is the best photo out of 115 I took while visiting Queenstown, Milford Sound and Doubtful Sound.

Lake Wakatipu, Queenstown, NZ
copyright by Kate Kyle

So I came back, well rested, shortlisted in Alzheimer's Blogging comp, did not submit my entry to RWNZ contest, never wrote that synopsis for the e-course, still unable to write.
I keep calling it 'writing drought' but it's not really a drought  - I have lots of ideas for novels, non-fiction books, articles and even a textbook! It's not a writer's block, because I know that if I sit for long enough I would just got it out on paper.

It may be something to do with not being able to commit myself to writing. I keep thinking: 'It's a brilliant idea I need to write that book proposal, but which publisher I send it to?' But there are so many publishers that I could submit my book proposal to, I don't know which one to chose. So I then think that I need a agent first. But I need a book proposal to submit a query about. But how do I write a book proposal if I don't have a publisher in mind. And da capo al fine.
I just can't be decide, and so I spend another evening watching one of my favourite sitcoms on DVD and pottering about, feeling like I still have time, while I don't.

Has any of you ever had a similar problem? How did you overcome it? Any ideas how to break that blimmin' vicious cycle?