Christmas cactus is a tropical cactus, not a desert cactus so it requires humidity to thrive. Stand the pot on a tray with wet gravel to provide humidity and mist the leaves. They also require about 12 hours a day of total darkness, so an ideal place to put it during the night would be a bathroom.

Have you turned it round? This can make buds fall as they try to turn toward the light and are not strong enough to manage it. If you do have to move it make sure that the light is always coming from the same direction but now it is already flowering I wouldn't worry too much about the period of darkness now - but remember it for next year.. They like fairly good light but not too much strong direct sun. (Not much of that around at the moment!) Also make sure you have not positioned it above a radiator as it would hate the current of hot dry air. Mine have always done well with the normal cycle of natural daylight and are happy in a cool conservatory.

Is it a new one,Dave? if so,the change of environment will also have affected it ..especially if it was bought with the buds already formed..it will be fine next year,if you follow the advice above..

PS - the bit about not turning it round only applies to when it has flower buds, not the rest of the year.

good point Sue..mine might have to find a new position this coming year,as it's getting too big for the bathroom window ledge..obviously a perfect place...but it will be either on top of the fridge Freezer in the Kitchen,or a Jardinere in the Conservatory,when it gets warmer in there..any suggestions please?

Difficult, not knowing your house Sandra. I have a peace lily with the same problem and have to draw the curtains very carefully! If you've got room for one of those stands that the Victorians used to love you can use that but its an expensive solution. Some churches and chapels have them too, so if one is closing near you....
Mine live in the conservatory in winter and mostly go outside in the summer but the conservatory is frost free.
They don't seem to mind low temperatures as long as it doesn't freeze.
Another solution is one of those very Seventies string pot holders that you hang from the ceiling, which work very well for the more dangly ones. All the ones I see on here are very lush and cared for looking, which mine aren't - but they do flower profusely every year, and the first one is just opening now with no heating on. I thought I'd mistimed it but its going to be spot on for once!

I might try mine in the Conservatory then,Sue,as mine is frost free, but cold..It does get morning sun,with it being east facing,as does my bathroom,but the heat is diffused in there,with the frosted glass..I can move it in the hot weather.and the Jardinere I have will be fine..as it's a tall pedestal,with a removable planter on top...I will move the Fuchsia that is in it at the moment,to the bathroom ! all sorted :o) thanks..