Grama-Herc, I have the same 'thing' about people coming into my space. When I want to have somone over for dinner as I sometimes do, if only to reciprocate for dinners I have been invited to, I do it at my sister's house while she is away!

I cannot imagine having to cope with an invasion like the one you are facing. My heart is racing just thinking about it on your behalf.
I agree with Nicolette's suggestion that you get out. As often and for as long as you need to.

And if going out is not possible, how about a polite sign on your door? "Meditating do not disturb" or some such thing.

And most important of all! try not to berate yourself all weekend for being 'unsociable, not a good hostess, etc.' That is my favourite way of making barely tolerable situations truly miserable for myself.

Oh...and keep breathing!