Flea Infestation

A few months ago contractors that I had hired let my cat out. She came back pregnant and had kittens at home a couple weeks ago. I am assuming the fleas came from her since she was outside for a long time. I can’t give her or her kittens treatment according to my vet due to her nursing and them being only a couple weeks old obviously. I gave my cats the topical medication from my vet yesterday which either hasn’t worked yet or isn’t going to because there are TONS of live fleas on my cats and no dead ones whatsoever. I’m just at a loss of what to do currently since some of them can’t be treated and I don’t know how to remove 8 cats and a dog out of my home to bomb it or anything if they still have an active infestation because they’re just going to come right back in with it so I’m confused on how that even works.