You aren't alone; I suspect many who are reading this have had a similar experience. Christmas is a very busy time for many people, and it leaves them exhausted -- and even wondering if all the busyness was worth it. They also may feel burdened over all the bills they'll be facing.
Nor is it only at Christmas that this happens; sometimes life's greatest highs are followed by life's greatest lows. It happened to the prophet Elijah; shortly after his great victory over the prophets of Ba'al on Mt. Carmel, he fled in despair into the wilderness. He prayed, "I have had enough, Lord.... Take my life" (1 Kings 19:4). But God didn't do this; instead, He assured Elijah that He still had work for him to do. He also refreshed him with rest and food.
If the holidays have been particularly busy for you, take time to get some rest -- and don't feel guilty over it! Jesus needed times of rest, and so do we. In addition, take time to plan for next year; if you did too much this year, decide what can be trimmed from your schedule next year.
The most important thing you can do, however, is to pause and let the true meaning of Christmas refresh your soul. Christmas should be more than gifts or parties or times with family. At Christmas, we remember God's love for us -- love so great that He sent His Son into the world for our salvation. Let His love fill your heart throughout this holiday season.