Envious of a Cat (Cat pregnancy/birth)

We have been feeding this feral cat that we found living under a shed with her litter of kittens on the (empty) property next to ours since the spring.  We now have adopted one of the kittens and are fostering a second who was hit by a car and needed a lot of surgery and recovery.  (The third kitten unfortunately disappeared.)  We realized a few weeks ago that the mother cat--who we were never able to trap to get her spayed--seemed pregnant again.  She got ravenous and extremely friendly a few weeks ago and seemed to be hanging around our yard constantly for the past week or two.

On Thursday she I fed her and saw she was bleeding a little and I figured she was going into labor.  We ended up bringing her into our laundry room for her to have the babies so we knew they'd be safe.  And on Friday morning we brought her to the Humane Society and they will be fostering out her and all the kittens until the kittens can be weaned. 

The whole thing was sort of fascinating to see.  She was amazingly affectionate and just wanted to be petted constantly right up to the point where she was birthing the babies and after.  (I guess that is something that can happen when cats are in labor?)  She paced and panted just like some women in labor do.  Unlike human birth, though, the whole thing happened amazingly quickly.  I found that she was bleeding around 9am, around 12pm she seemed to be getting into active labor, and she had the first baby around 1:30pm.  In the end she had 6 kittens, all seemingly healthy.

Anyway it was an interesting experience to see, though also sad.  I cried a little when she had the first baby because I just had this sense of "I was supposed to do this--I was supposed to have a baby.  I did have a baby--but I was supposed to have a baby that *lived*."  I feel sort of like, how is it possible that this cat is able to have 6 healthy babies (right after a previous litter), and I couldn't mange two (or even one, after the first twin died)?!  She had been looking pretty ratty lately, like her fur was thinning so I assume she just couldn't get enough nutrition in for all of those babies even with us feeding her.  And she was living outdoors in the middle of a very hot summer.  And her babies are fine!  I know, of course, nature designed cats to have litters of kittens while humans are not well situated at all for multiple pregnancies.  But still.  Silly as it is, I'm kind of jealous.