Grit your teeth and just do it,... Seriously. I have to do the same next week and once I'm there, like you, I'm fine but I've been useless the last couple of weeks and tomorrow I'm just going to have to finish, go and reluctantly do my class and keep doing that for the rest the week until the endophines kick in and my old mind set returns... It's less about motivation and more a kick up the elbow that works for me... I know I have to do it but it doesn't mean I have to do it with a good grace damnit! ;0)