I have been there as well. It sounds like you are being set up at this point, and there will be no way to dig yourself out of this hole. They want to get rid of you, so now they are just making sure they have the correct paperwork in place. It is a self-esteem crushing experience, trust me I know.
My suggestion is to disconnect from the job emotionally and just go in and check the boxes. Spend all of your concentration and emotional energy on finding a new job. That way you can leave on your terms, which is so much better.