Girl has a disease that makes her listen to a soundtrack in her mind/imagine herself on videoclips

Okay so I do remember is a black girl and she has a black best friend that can also be her sister, and she has a white brother that I think the actor was a viner, the ting is that she take pills so she can stop her mind of creating this video clips in her head and during the movie there are lots of songs that she sings with the other character lika a musical but its all in her head