After Trixie dies, Starlight resorts to alcohol and shuts her self in Trixie’s wagon. When Twilight and the others have to go on a trip to save Equestria once again, Starlight wanders around the town drunk till a few ponies take her home and help her.
(Alternate ending in this universe https://www.fimfiction.net/group/217012/sunsets-and-the-others-lives. Here's the group if you wanna join.)