I also have a 2 1/2 yo child and I understand that you are exhausted, I am exhausted too! it isn't easy, it isn't easy at all...
what about taking her to the kindergarden, so that she can play with other children and you can have some time to re-center? then when she comes back, you can give her some time of un-divided attention. I wouldn't survive long without kindergarden, and my son loves it too very much.