Sheebeen, Well done!
It really was best to tell your family be it Christmas or whatever. There is never a good time just a right time.
Your mothers reaction was identical to what happened in my own situation.
She screamed and cried and thought I'd chosen to be gay. She asked me to change because it was a terrible life being a "lesbean". She tried to set me up with every farmer with a jeep and 200 acres!
My mum has led the best part of a sheltered life. She'd only ever seen a lesbian in the distance and even that was only a rumour. One of the first questions she asked me was "who else had i told"
And she flipped when she realised most of my cousins knew already. Anyway, enough about that!
I stayed for a few days and although she hardly asked any questions about my lifestyle she accepted it as my choice, my life. She just needed to know I was safe and not gonna be in any danger.
Now, 6 years later its hardly mentioned. My missus sat at the Christmas table this year, treated like one of the family. Time is a great thing really.
Your mum sounds like a great strong woman! Keep talking and I'm SURE with time everything will be fine.
By the way, I know it may be hard but the sooner you get over the awkward atmosphere the sooner she will.
I cuddled my mum at every available opportunity afterwards! In her eyes your still her baby!