Hi. I'm Dr. Lee and will do my best to help.
Is she eating and drinking normally?
Any vomiting or diarrhea?
Any coughing or sneezing?
How long has she been sick?
Thanks for the info.
I would be concerned about urinary tract disease, such as infection, bladder stones, and blockage, especially if she hasn't urinated since yesterday. All of these will lead to pain and thus the arched back. And since she has been sick for 2 days already, she really needs to go to the ER as soon s possible. Blockage can be an emergency situation. She needs to get an exam, and possibly x-rays at the ER immediately. Other possibilities include GI obstruction and pancreatitis. Both of these are also urgent issues, thus also require going to the ER.
Please let me know if you have any questions or concerns. Thanks.