Suzzie, you DO matter sweetie, you DO deserve a life, happiness and time off work to relax! these people are horrid taking advantage of your good nature, but it can work both ways, once worked for them, you have every right to say NO next time and you have a valid reason when you say no next time, because you gave up this christmas for them!!! we live in a world where people often need reminding of the give and take rule, most only remember the take bit, Also i am not sure what the employment laws where you live are but i would start questioniung youe boss about the perks of working holidays, over here they include double pay and an extra day off for each holiday day worked!! maybe if you find out the perks set out by your country government and employer then point these out to him/her you may find they think twice about asking you to swap in future!! they may be using you because you are not aware that they are not giving you your full entitlement!