Plans for the long weekend

I've been struggling a bit. When I get home after work, I've barely any energy or brain-power left. I need the weekends off to charge myself up. Which leaves me with the dilemma, when to write? If it was November, I'd try to force myself, but this is different from NaNoWriMo, where you only need to concentrate on the quantity.

Aside from that particular month, I need to be an editor AND a writer when I create. It's especially true now that I'm revising Book 1. Which brings me to another question: do I finish the revision of Book 1 and then finish the first draft of Book 3, or is it alright for me to just continue Book 3 when I feel like it, regardless if I finished revising Book 1?

Now we have a 4-day long weekend, and I've been on holiday this week, so I'm supposed to be well-rested, recharged and ready! But which one to work on? Book 1 or Book 3? And the eternal question: why is it so hard to start? Once I start, I usually continue more easily.

... I think my problem lies with where I am with Book 1. I'm almost completely rewriting a storyarc and it's not easy, at all.