I had the same deal several years ago and concluded that we had walked them in. You have to treat everything. Beds, yard, inside of the house, pet. DE is good for the yard. Gets into the chinks of their armor. Put part of a flea collar in your vaccuum cleaner bag. You can get some good stuff at Petsmart for the carpet, spray on, hoover up. Once you get that all done, you might need to do it again in a few weeks. Flea larvae eat organic stuff, so you have to clean the furniture. It's a mess, but you can do it. It took me all one summer to get rid of fleas, but I did it. Just had to figure out a way to go about it.