Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your situation, and wanted to help.
Now I have to note that you mentioned the use of Advantix twice for your kitty. The problem with that is that there is no Advantix for cats. So, if you used this (and not Advantage or Advantage Multi), then it is highly cat toxic and we'd want her seen urgently.
Now hopefully it was one of the cat intended products that you meant. If it was, then we do tend to rinse it off using cool water and dish soap (sometimes we even have to shave the fur to remove it all). Since these signs are bordering on neurological and seizures are a risk, we would need to keep her calm, quiet, in a dimly lit room and reduce any stimuli that could push her into a seizure (which is especially worrisome for a diabetic as it could throw off her blood sugar).
Overall, you are not over-reacting at all. And if you used Advantix specifically, then we'd be quite concerned and want her seen urgently for symptomatic care.
Please take care,