Finishing a draft is a strange feeling. You know you've accomplished something, but you don't know what. You aren't finished the project. You already have improvements in mind for the next draft. You get a sense of moving forward, at least. But how far?
You won't know until you read your draft, preferably in a single long sitting. It's strange to print out a whole book, and holding the manuscript in your hand, and have no real idea what it is you're holding. Its seems familiar yet alien.
Best to take a day, or an evening at least, to relax and unwind before you dive into the sharkwater of the next draft.