I don't know what it is about the last couple of months, but a fair few authors have been struggling to produce the goods of late.
David Bishop has this to say on the subject. Nick Kyme's struggles are catalogued here. Chris Wraight's been feeling the pressure too, as has Si Spurrier. Even the mighty Dan Abnett has had his own creative demons to battle of late.
And I'll add my own name to that list. I thought my tenth novel was hard going but as it turns out, that one was a walk in the park compared to number eleven. Soul-destroying is how I'd describe the situation right now.
Writing's hard! :-(