I'm in Love and It's the End of the World

I'm in Love and It's the End of the World (地球のおわりは恋のはじまり, "Chikyuu no Owari wa Koi no Hajimari") is a shojo manga by Taamo. It ran in Kodansha's Dessert manga anthology from November 2015 to October 2017. It is complete in five volumes. Kodansha Comics has licensed it for digital English release.

Plot
All her life, Mahiru Yanase has always been second best to her twin sister Mayo. Mayo is cute, popular, and sweet, while Mahiru... isn't. Mahiru always reminds herself that anytime something good happens to her, something bad will happen to balance it out. However, on her first day of high school, her handsome and mysterious classmate, Aoi Satomi, takes and interest in her, and has asked her out by the end of the day. Mahiru is certain that if things don't balance out soon, the world is going to come to an end!

Official
Official English site