It came out over a year ago. It was about Ditzy Doo, who was just suddenly brought into existence, meeting Derpy, and the two of them going on an adventure.
Things I remember:
Ditzy was intelligent, cynical, and actually despised Derpy for the first part of the story.
Derpy was Carrot Top's roommate, and Dinky was her child.
WARNING FEELS! Dinky was a product of forced work place sex, because Derpy wanted to be accepted.

Things I don't remember:
The ending, but I'm pretty sure Ditzy dies, and Discord "may" have been involved.
The name
The author

If any of this rings a bell, can you notify me please?