You are lucky you didn't do it the other way round. Never, ever give flea treatment to a cat that should be for a dog. What is packed for dogs and cats should be given accordingly. Anyway Iam sure your dog will be fine she still loves you,. I got this severe warning from my vet (I did the same thing) believe me he wasn't laughing.
I am almost absolutely sure Frontline is the same ingredients for dogs and cats, and the only different thing would be the dosage for the size of the dog or cat. (Not all flea treatments are, but I think Frontline is) Please do call your vet and verify this though.