I started thinking about a trip last Tuesday, started lazily scanning for hostels/hotels Wed and finally booked something on Friday morning. That left about 4 hours to get packed up and out the door Friday afternoon. It was a great trip, but definitely not the most organized!
It sounds like you've got the general stuff in order, I wouldn't worry too much about the motivation - that'll come as you get closer, or at least when you start off to the airport...
If you're worried about having everything in place in time, you might want to make a list of all the things you NEED to do before the trip (insurance, picking up any last minute stuff, packing and whatnot) and starting with the most time critical things first (maybe the insurance, if that takes a while), knock off one or maybe two things on your list each day. Then you'll feel like you're doing stuff, get a sense of accomplishment (good for motivation) and not have a last minute panic and spend the last two days rushing around like a headless chicken.