It tells us, among other things, that she realizes that she has a very isolated and extreme perception of reality. It tells us that she has questioned her own perception of reality as possibly being incorrect to the point of her being "insane."
She is telling us that she has wondered if she, herself, is indeed incapable of functioning in Ameican society.
Oh yeah, Rashida. Call me insane! CaLL mE InSAnE!
The Squad video on Youtube (2:28 min.). Love that vid...