Ok so after years of meaning to get to this short series, I finally did.
Well, I did... AND WOAH.
Wasn't able to find a thread for the anime when I searched, so I'm starting one now.
http://www.animenewsnetwork.com/encyclopedia/anime.php?id=784
Otani Yuri, much to her disgust, has been elected by her class for alien fighting duty. Together with Tonime Kasumi, who joined the alien fighter simply for the sake of doing so, and Kawamura Kumi, who became and alien fighter to avoid the responsibility of yet another year of class presidency, she must defend her school from periodic alien attacks. Introspection, fear, anxiety and friendship await Yuri as she is forced to stare life itself in the mouth in her chaotic coming of age.
Spoilers (well, on content):
I've seen some effed up crap happening to children in anime. But this took the proverbial cake. This series utterly must be one of the most upsetting shows that isn't actually full of gore or upsetting spoken word. It just... I don't even.
I remember seeing the manga on the shelf of my local bookstore but never buying it, but something about it always piqued my interest... need to read it now, as I really would love a ton of questions answered.