Phal losing leaves....HELP!

[Malia_R]

My phal has been going very strong for the past 4 months over winter. But all of a sudden the flowers have quickly wiltered and fallen off and the leaves have turned green, then red and then fallen off too.

I have lost 2 leaves now and it looks another 2 are heading that direction! The only thing that is giving me hope is that there is a new leaf growing at the top that looks very healthy. But I'm scared that if the other two leaves drop that there isn't much hope left for my precious phal.

I have been watering my phal once a week. It is positioned in a well lit spot without any direct sunlight. What could be causing the leaves to drop? Is there anything I can do to save it?

I have attached 2 pictures. 1 when the orchid was in bloom. The 2nd of the leaves now.

Thanks in advance for your help.