My cat had one kitten, then two.. now what?

Question
Hi there,
first of all, I'd like to thank you in advance for reading this, and hopefully helping me out with my question/concern.
We had suspicion my cat was pregnant weeks ago, and as it turned out, she showed all symptoms and began looking bigger and bigger.
On Tuesday morning, we walked in to her "room" to the suprise of a kitten nursing. My cat - her name is Scarlett- seemed calm, tired, but still very loving. The kitten was a good size, very normal [in reference to the things I've read about newborn kittens], the kitten is eating well, and just.. all in all, seems healthy and well. So, we figured she only had one kitten. But, this morning, I walked in to her room again in the morning, and SUPRISE, another kitten. I dont know if it is normal for her to give birth to one, wait 24 hours.. and give birth to another. Is this rare, or common? Does it mean anything about Scarlett? Will it have any effect on the kittens?
Also, I still feel a very distinct object [lump] in her tummy as of now..
does this mean there could be another kitten tomorrow morning?

thanks for reading, and hopefully you can help me out!
-Ariel

Answer
Ariel,

This is not uncommon.  I am glad both kittens are doing well.  It is possible that she emptied one horn of the uterus yesterday and one horn today.

Did you count placentas?

I would have her to the vet to see what the lump in her abdomen might be.  It would be quite unusual for her to have waited another 24 hours to have head a third kitten.  At any rate, the vet will probably give her a shot of oxytocin which will help clean her out, shrink the uterus, and help in milk production.

Best regards... Norm.