Lionheart pretty much just said what I was thinking
I also had my mom stay over the holidays, and it was the toughest time I've had... chrissie combined w/ the fact that mom and I usually drink wine together.
I think what Lionheart said about creating a new routine/ ritual w/ your mum is key.
When my mom was here we stayed busy... shopping, walking, theatre, visiting friends etc., which helped keep my mind off of other things.
Good luck, you can do this and I bet you'll feel really good about yourself when she goes home and you realize you've overcome another obstacle. xx