Maybe its common, but I never had those thoughts..and no I didn't have a lot of help..dh worked and it was all me..both times. And my second was very fussy while my then 18 month old hated the new baby for a good week.
But yea that's. scary.
Edit- for those who like to twist things...I feel sad for them. Sad as in wow I wish I could do something...not sad as in "they are sad people"
Maybe scary wasn't a good word to use but seeing all those women talk like that IS scary.