I find it's always hard to come "back" from a week like that. But getting back to a normal schedule, and normal productivity, is important to do as quickly as possible. Here's how I'm doing it this week.
Planning out my week ahead of time: I find that I'll get back into my normal routine more smoothly if I have a good idea of what has to be done during the next week, so the first thing I did Sunday night was to sit down and make a to-do list. That way I knew not only what I had to do throughout the week, but also what I would need to do each day. Since my tendency after a few days of a week of not working much is to be easily distracted when I try to go back to work, having a list helps me to stay focused.
Scheduling several dedicated work days (or mornings, in my case): I tend to have a lot going on in my life -- I have two horses to ride, plus weekly riding lessons and weekly physical therapy appointments for our dog, and that's just the weekly stuff! -- but I've found that dedicating a few mornings in the week to my "usual" work routine helps me to get back into the swing of things more quickly. Today was one such morning, and tomorrow will be another.
Minimizing distractions: I am terrible about getting distracted when I'm supposed to be working, but I do have a few tricks that work well enough in the short term to get me working (productively) again. Putting my phone in a different room and blocking Facebook on Firefox using LeechBlock are a couple of them. I also sometimes set a timer for a short time period, such as 30 minutes, during which I make myself stay focused. Seeing that I have so many minutes left before I can take a break often helps me stay on task!
How do you get back to work after a busy week or some time off?