Christmas should be a time of joy and celebration and for good reason, because it reminds us of the coming of Jesus Christ into the world to save us from our sins. Like the angels on that first Christmas night, our hearts should be full of joy and praise at Christmastime (see Luke 2:8-14).
Unfortunately, I'm afraid Christmas isn't like this for most people today and that is tragic. Instead, Christmas becomes a time of frantic schedules and overspending and other pressures and Jesus gets lost in the process. Every year about this time, I get several letters just like yours, saying how much they are dreading Christmas (although their reasons may be different).
Why do I mention this? One reason is so each of us can pause right now before the Christmas rush overwhelms us and resolve to make this Christmas different. Don't leave everything to the last minute ... don't feel like you have to do everything ... and above all take time each day to turn your heart toward Christ.
This Christmas "May the Lord make your love increase and overflow for each other and for everyone else" (1 Thessalonians 3:12) including your relatives. And consider visiting some of them at other times, such as at Thanksgiving, so you can have your own family Christmas.