After an extended period of travel, getting back into the swing of a normal day-to-day routine can seem stressful and overwhelming. This is especially true when it comes to work-related tasks: coming back to an inordinate amount of emails, pending deadlines, and just office life in general is often hard to manage after spending a week or two away. To make the transition from vacation to work go a little smoother, do these things before even boarding the plane.
Wrap up any unfinished business: Before you say, "see you later" to work, finish up as many projects as you can - this also includes getting through all of your email. It'll keep you from worrying about all the stuff you need to catch up on once you're back, and you can relax and enjoy yourself. It's also much easier to come back to the office when you don't have a pile of folders waiting for you. If it's impossible to finish every task on your desk, leave yourself notes about the status of where you're at and touch base with any colleagues that are working on these projects with you.