General Smores Mysteriously Became Pregnant!?!?

So turns out Smores who I thought was overweight was pregnant..

This morning as I was going down to get breakfast Smores made and awfully odd sound that made me stop in my tracks, it was nothing I've heard before. Eventually she ran into a hay house which I picked up so I could bring her on the bed. Once on the bed she made a few noises then started hunching over and I noticed a weird thick liquid under her, which terrified me because when Peanut died a very similar liquid came out of her so I thought something was terribly wrong. Minutes later there's a tiny wet guinea pig in front of me!! Over the next half hour she gave birth to three more, the last of which (Chippy) did not survive. Chippy survived about an hour but wasn't very active or breathing well during that time so I'm curious as to what happened there as well if anyone can help me with that.


However the big question I have is how in the world did she get pregnant!?!? Her cage mate, Coffee, is a neutered male. Is it possible when he was neutered it wasn't done correctly? I adopted him when he had already been neutered, so this was not of my doing so I do not know where he was neutered or by who. But there definitely is no penis on him, I'm worried now because I don't want any of my other girls to become pregnant nor do I want Smores to be again either. Not to mention Toffee, the second male I adopted is neutered as well. Toffee seems to be more laid back and hasn't mounted his cage mate Bandit but I'm still concerned for her as well.


I adopted s'mores on February 20, 2018 so it's not possible she was pregnant the entire time correct?


Also any other advice for taking care of pups would be greatly appreciated as I haven't dealt with newborns, only two to three weeks olds.

Attached photos of the cuties, minus Chippy I didn't have enough time before she passed to get any