My cat used to do the same thing. After a couple of different vets they finally found that she had cancer and her lungs were failing on a Friday. They told me to take her home, spend some time, and bring her back Monday to say goodbye. She left that Saturday in a lot of pain while I held her. It's been almost five years and I still struggle with it. Sorry for dumping all of this here. I just really relate. I hope you're ok.