When I was living in NC I had a hell of an infestation one summer, thanks to my cat. Getting rid of them is a long process because one of the stages in the life cycle is basically invulnerable. Here's what I did.
I gave the pet a Capstar, that will kill any living fleas on the pet for 24 hours. Now get the pet out of the house. Spray your carpets with Raid Flea Killer, which is just a bomb in directional format. Let that soak for a few hours. Then vacuum the carpets. Furry friend can come back. Update their topical flea treatment, and for good measure, another Capstar the following day.
The key is to keep vacuuming. The Raid kills the living and baby stages, but the the pupae (or whatever stage is invulnerable) will keep living. Keep vacuuming, daily, for at least two weeks. I promise you can beat this, but you've got to break the life cycle of the flea.