I would let her invite a friend over, give them flat sheets and the let them build in the dining room. They amuse themselves, you get a few minutes away. If there’s story hour at the library, take her to that.
Get out of the house in a non-shopping situation. Take her to the playground, walk around the neighborhood, take the car to the carwash, and let her watch it go through, go to a cemetery with a pond and let her feed the ducks, that sort of thing.
If you’re home with with her 24/7, you need to make sure that you are giving her chances to learn how to amuse herself and play without depending on interaction with you. Sometimes this means your house will be a mess. Things like cardboard boxes, craft supplies, etc. facilitate self-play.
We had a brief period where we would all lay down in our rooms for 30 minutes and listen to audio CDs from Classical Kids—Beethoven Lives Upstairs, The Magic Flute, Bizet’s Dream, Tchaikovsky Discovers America, etc. Those were good at bedtime. We also had the Little Thinker tapes, which were descriptive stories of scenes which prompted the listener to stop and draw a picture of the scene, then start the tape back up when they finished the picture, and draw the next scene.
I found that periods when my children were the most frustrating were usually followed by a big developmental change. Also, for some reason, there seemed to be a cycle of six months of being Miss Cranky Pants, six months of being St. Angelica. I really think it’s a developmental thing. Focusing on that helped me endure.