Answer:
This could mean she was distracted from her sadness by something happy like she was said and now they are watching her favorite show and she forgot all about it.
Or it could mean she is sad about a lot of things and is feeling them all at once.
Or it might mean that she stopped caring about that thing and wonders why she was sad in the first place
Step-by-step explanation:
It all really depends on the context. I hope this helps. Have a great day!