There's a tradition in the Canadian Unitarian Universalist church (and perhaps in other churches as well, I don't know) of having a December event called Blue Christmas. It's a special service of meditation and readings which acknowledge and honour the fact that Christmas is not always a happy time for everyone.
For those who are ill, alone, grieving, depressed or in difficult circumstances, Christmas can be an excruciatingly painful time with its single-minded emphasis on fun, family, jollity and high spirits. Christmas can be salt in the wounds of many.
It's important not to force expectations of Christmas joy and merriment on those who don't feel it for whatever reason. It's okay not to be happy at Christmas and it's okay to need emotional support to get through it. Hugs, understanding and no pressure are the best gifts for us to give.