Hi Basil,
I recommend posting a photo if you think something is wrong with your orchid. I suspect, as Ron has said, that it was probably time for the flowers to fade. If, however, it was actually buds that fell off, then there may be a problem - especially if you have had it in the same place for several weeks and it seemed alright. Best way to get the best advice is post up a photo and let the members here who grow phals take a look at it for you. Include a full shot of the plant and any problem areas. If you take the orchid out of its pot, photograph the roots as well.
Cheers,
BD