It sounds like you have a sick cat and it's unlikely that insulin is the cause.
There are two serious conditions associated with diabetes, one is diabetic ketoacidosis, Larry mentioned testing for ketones because that's the measurable indicator. To test you will need ketostix, which are available at any drugstore. They are usually kept behind the pharmacy counter. This is a urine test, so you will need to catch Ginger in the box, not easy, but necessary.
The other condition is Hepatic Lipidosis, also called fatty liver disease.
Both DKA and HL can result from a cat not eating, that's why Larry mentioned syringe feeding. BTW Larry is a vet tech and very knowledgable.
The ketone test will tell you if Ginger is a candidate for DKA. The urine testing sticks give a rough measurement, if the reading is negative or small you can treat at home by force feeding and giving insulin. If the ketones are moderate or large you need to go to an emergency hospital because Ginger's life is at risk. It will be expensive, but the sooner you go the less treatment will be needed.
I am not trying to scare you, but I am concerned because you have so little information and so little experience. Here is a link
www.marvistavet.com that will take you to a description of many feline diseases, look up diabetes, DKA and Hepatic Lipidosis to get some basic information, then come here with additional questions.
But before you do anything else please get the test sticks and get a urine test. You need that information before you can proceed.
People here have experience with both conditions, so do come back as soon as you know a little more.
Gia & Quirk (GA)
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