Lyric discussion by Mattyboy1023 

Cover art for Skin and Bones lyrics by Foo Fighters

It sounds to me like whoever the song is about is in a relationship to where the other person has taken everything away from him and left him as only "Skin and Bones." And that he's tired of it because everything has changed for him "All worn out and nothing fits." And also that the relationship has caused him to lose previous friendships("Tell my mom I'm doing fine") maybe.