Please don't apologise. It is better to post than to keep it all inside. Plus the spirit of Christmas in my opinion is to think about others not all the present giving!
I wish i could say something that could allow you some relief. I know how blummin' difficult it is maintaining a facade.
I'm sorry i do not know you personal circumstances but i have been part of that battle with life and it is so hard.
All i can offer are my prayers, love and support. I hope these give you some energy if even for one more day.