MIL throwing late babyshower

So my friends threw me a friend/coworker babyshower in early Dec. because they knew the earlier the better. My MIL had always mentioned she would throw me a babyshower and I just found out it's at the very end of Jan. Just two weeks before my due date. I hate to sound ungrateful but I am DREADING this babyshower and would rather she not do anything at all. I know she means well but I am suffering from excruciating pelvic girdle pain and I can barely get around as it is! Not to mention that my morning sickness never went away and I am feeling the swelling. My husband mentioned that it was too close to my due date and she just said "oh it'll be fine". The reason she is doing it so late is so that my SIL can make it that day from out of town. Now I don't know how to say no thank-you without sounding like a total b*tch. Lastly, I plan to have everything I need by that time for the baby, so anything I get I will probably already have. Anyway to get around this nicely?