Hi: This can be a pretty serious toxicity. First of all, tonight, right now, give your cat a bath with Dawn dish soap and water. Try to get all of the flea product off of her. Rinse very well after the bath to get all the dish soap off her. Secondly, call the ASPCA Poison Control Center at 888-426-4435. They will tell you if going to the vet right away is necessary. You will need this opinion. They are expert toxicologists and they know every product and every dose and have helped thousands of pet owners in your situation determine if emergency care is indicated. It will cost you about $60 to talk to the toxicologist. It's well worth the money. Let me know if you have more questions. Again, this can be a serious toxicity. Best wishes.
The best answer to any question regarding a sick pet will come from your own veterinarian, however, I am happy to provide information based on my experience.