I think nicknames / shortened forms of names are cool! It's interesting how people form the shortened name and it can tell you something about that person! (Someone I know took the last part of my name and uses that whereas someone else takes the first few letters...) Fun stuff!
Sarah, lol. Closest you can get is going by your first and middle, which I do pretty often.
Sasha is a possible nickname? (Sort of its own name but it still works) You are right though your name is tough...
The name ‘Sadie’ actually came from Sarah, fun fact. It unfortunately SUCKS. so.
Exactly the same for the most part... one friend calls me Amy, one Ame, and one Millie (I know you are talking about Kanye but still all relevant to what I was saying earlier) same sort of name breakdowns...