Welcome to FDMB
It is overwhelming I’m sure, but Feline diabetes is manageable, what insulin was Lily prescribed and what dose, the best insulin for cats are Lantus and ProZinc they are a 12- hour insulin and easy on cats. Also home testing is very very important, you do not want to give insulin without knowing Lily’s glucose level to avoid hypoglycemia, also a diabetic cat need to have a diet of wet can or raw foods between 0-10% carbs, also several meal a day is very important, what are you feeding, if you are feeding kibbles and grazing, the dry foods contain between 20-30% carbs cats cannot digest carbs, so when you switch from dry to wet, the transition needs to be done slowly, as for lack of appetite, there are several medication available, please continue to post we are here to help you on this journey, there are many sticky notes on the Main Forum that have much valuable information