Second draft blues

I'm not sure how other writers handle it, but the second draft of my second novel is so much harder than the first one. The first, for me, concerns story, so you're lay out the skeleton of the book, deciding who lives or dies or loves or seeks revenge. So far, good. But in the second, you're sculpting muscles and tissues, determining memories, adding landscape,charting backstory and future plans, in other words, you're playing Dr. Frankenstein.

My characters keep changing, especially at 3am, when sleep is nowhere to be found and all the mistakes of the day's writing are dancing in my head instead of sugar plums (what are they anyway?). Being open to change is good, but when it continues night after night, is that a sign that I don't know which direction to take? Or does it mean I'm flexible and able to shift when necessary, when the characters demand it? But if they keep shifting, they may steer me right into a padded cell.

God almighty, will I survive to do a third draft?[image error]