I've had a couple of people notice that I went about 2 weeks without posting and then all of a sudden a backlog of posts just flooded my blog. Although your guesses as to why this happened were good and reasonable, here is the true story of what happened.
I got behind in blogging.
I felt guilty.
I spent 3 hours one night uploading pictures and typing.
I published a bunch of posts and changed the dates on them to make it appear that they'd been there the whole time.
Aren't I sneaky?!