Angry Christmas Feelings

I am having angry feelings now during the holidays because I am not able to be with my husband because he works in Nigeria – he just left yesterday for  a month (he works rotational a month and returns for 3 weeks).    I am having trouble getting motivated to buy gifts, send cards or plan any holiday meal.    We have never missed a Christmas and I feel deprived about this, and I know others are probably having more difficult things to worry about but I cannot help it.   I am not accepting his work very well and this is just another example of my rejecting the work overseas, which I cannot change.  What should I do to feel grateful and not angry when I see everyone going to parties and dinners and shopping and enjoying the holidays together, which is what I really like about the season?  I know helping others is one way to get your mind off of your own situation and I know this, but it does not help me.  I still feel anger.