If A Cat Has A Dual Pregnancy, Got Pregnant Twice Over A Week Apart When Will She Give Birth?

My cat gave birth to 4 kittens on a Sunday. Then on Wednesday she gave birth to another kitten. Now it's sunday again (a week past her first birth) and I think I can still feel another kitten. Can she possibly have yet a 3rd birth?! No one believed me when  I said I knew there was another kitten inside her, but then she went ahead and had it 3 days after, so I was right :). I just can't imagine for the life of me her giving birth a 3rd time! But it feels exactly just like when I thought there was more the first time.
(Just so you know, the 3 day late kitten came out perfectly normal and healthy, but one of the first litter kittens passed away.)

In cats, litters can have multiple fathers, but the litter will be delivered all at once.  Litters can range from 1 to 13 kittens, with an average of 4 or 5.  Generally the interval between kittens is 10-30 minutes but the mother may rest a long time between delivering each kitten.  However, more than 12 hours between kittens is probably the time to call your vet.  And if you don't know how many kittens your cat was carrying I would suggest that you should see your veterinarian.

The way it works is that when a female cat is in heat, she will seek a male.  The act of mating will stimulate her to ovulate multiple eggs.  These eggs are then each individually fertilized by a different sperm.  This may be from one or more males.  The fertilized eggs will then spread out and implant along the uterine horns and develop to term together.

Female cats have been known to accept other males to mate at days 10-14 of pregnancy.  It has been reported that this can result in a second younger pregnancy. This is called "superfetation".  However, it has not actually been scientifically proven to occur.

If a cat has a dual pregnancy will she give birth at the same time

What the heck do you mean by Dual pregnancy? A cat can be pregnant by more than 1 male, but will have the litter at the same time, this is one reason for runts and stillborn kittens.

I don't know how that works but my Himalayan cat had three premature kittens on Mon 14, they all died.  Then today she had another one who seems healthy.  How is this possible, I have been raising cats and dogs for over 20 years, and have never seen or heard of such a thing.  Has anyone?

is it possible for a cat to have 1 baby and then a week later to have more kittens