AAAAHHHH! Gossip first have a 
or a 
now it is after 6.
Then sit down and write a list of everything that you need to do.
Then take each day between now and Christmas and figure out when you are going to do each thing. Write this down.
Then delegate any job you possibly can.
Then have another or and get started.
I would imagine that the shopping is priority as it can be wrapped in the evenings etc. Most shops are open later into the evening this week which also helps.
Can you bulk out the stockings with things you would have bought anyway such as toiletries, pyjamas and new undies or have you done that already? Primark fleece sleep suits are only £6 for dcs and fill up a fair bit of space. You get them for adults too but you and dp may not be in that zone yet.
Or be clever with your wrapping and wrap little things in a box, in a box, in a box, that sort of thing?
John Lewis were selling MASSIVE gingerbread men. They did cost £5 each but they are huge and would fill up some space.
As for food, have you every had a turkey crown? My parents do this if they don't have an enormous crowd of meat eaters on Christmas day. There still seems to be plenty of turkey.
Will you do another Christmas style lunch with your dp on Boxing Day or will it be more informal that day?
Ignore the chaos of the house, just get your sink and kitchen tidy enough to make cooking tolerable and if you are eating at table then get a great big bag and shove everything cluttering up the table into a big bag and deal with it once the chaos is over.
Let us know, step by step how you are getting on.