Oh poor Ratty!!
This is just a suggestion. I think it could be cystitis.
One of mine had this when she was 6 months old. She kept going to the litter tray and there was some blood. I felt so sorry for her i was at the vets first thing the next day. As we women know how uncomfortable this can be.

You need to get her to the vets tomorrow morning. or ASAP.
I would not give her anymore dryed food. Also try and get her to drink some water.

Let us know how you get on.
Good luck Ratty.

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