Lyric discussion by inconceivable 

Cover art for Supergirl lyrics by Krystal Harris

the song seems pretty clear to me...

It's about a girl who is very strong and she helps a lot of people, whether it be her friends or (in relation to the movie) an entire country. But sometimes she needs help too, and she's realizing that there's no one there. She needs someone to confide in but there's no one.