So I ended up looking around for the official and from what I can tell it has two volumes but as they aren't officially licensed yet, we only have what has been translated; which is only the five chapters. I crossed referenced with about three other sites and the results have been the same: only five chapters have been updated and all haven't been updated in about a year.
Now there was one odd one out on out on a site called bato, someone is uploading it over there, tho so far only the first two chapters has been uploaded and they've split each of the chapters up into about three parts each (if my memory serves me well). They started updating that nine days ago and most recent one was a week ago, if you wanted to try and wait for that one to catch up.
But other than that all of my research has come up dry (tho I'll probably keep looking cuz I'm invested now) sorry I couldn't find anything, but I hope I at least helped with any curiosity
On here it's called: "A Story About The Reaper and a High School Girl Who Will Die in 7 Days"
Alternative:
• 死神の花嫁-余命7日からの幸福一
•Shinigami no Hanayome: Yomei 7-nichi kara no Koufuku
•The Bride of the Death God: Evanescing Happiness
Artists/Authors: Ichiiro Hako
I was really liking the story but then on chapter 6 & 7 it turns into a completely different series. Like they uploaded the wrong manga. It left me on a cliffhanger! The story and art was so beautiful in the little that I read. If anyone can help me find the original source or let me know it discontinued that would be wonderful. (*´ω`*)