Oh, Gracie. I'm sorry. That's the most frustrating thing. Here's what I
do, and our heat/humidity is almost as bad as yours.
Advantage or Frontline *everyone*. Then get some spray for the grass,
and spray around the house and front yard, where you're walking. You're
tracking them in on your socks, too.
Usually after you Frontline everybody, the problem diminishes inside
the house. I've used the carpet powder with good results. Just leave it
on a while, then vacuum. YMMV. I don't have children who get down and
play on the carpet. So you might not want to put stuff on the carpet.
Your vet ought to be pretty educated about what's new, what's safe,
what works for indoors.
But I will tell you what does work, real well, too. Vaccum. Vaccuum
Vaccuum. Then immediately throw the bag in the trash outside and vacuum
some more.
Good luck. I've never called a prof. exterminator (yet). Let me know
what he says; what are they using indoors now?

Sherry

I don't know if you can get this stuff in the USA, but I use this spot-on
called Stronghold for my two.  It kills fleas, ticks, roundworms and
earmites all in one go.  You can only get it here from a vet.  It's quite
expensive, so I take no notice about the recommendation to apply it every
month.  (Vets like to make loadsa money after all.)
My two get it between their shoulder blades every three months or so, less
if I think they need it.
We seem to have no worms, fleas, ticks or earmites here ;-)

Then you have the problem about fleas/eggs in the carpet.  It might be a
coincidence but..regular vacuuming not only of the carpets, but where the
carpets meet the wall and also of the soft furniture, with my Dyson has
worked for me.  No fleas.

Tweed

My cats have no fleas, even though they go outside all the time.

They aren't as bad here as in the humid south.  But everyone gets advantage
once a month whether they need it or not.  But usually only half a dose.

If the get into the house.  I get everybody out for a hour or two and set
off a couple of bug bombs in the house.  I'm pretty sure the one I use are
Hot Shot.  Its an orange can and it isn't messy.  Then shake out pillows and
blankets, wash all the bedding, and vacuum everything that can be vacuumed.
Our vet said that flea eggs vacuum up really easy. And wash out of stuff
really easy.  Usually I'll throw all the pillows and blankets in the dryer
for a bit too if there is a real problem.

Now here is the trick.  Do it all over again in two weeks even if you don't
think you need to.  That is when the ones you missed will be hatching and
you need to kill them before they feed and lay more eggs.

Jo

My cats had fleas in the pre-Frontline etc days, and my vet clinic sold me
a mousse for the cats (which you would not need with the newer methods)
and a spray for surfaces the cats were on. Of course, that included every
surface in the house!

Still, the combination worked.

Try Revolution.