So i accidently stole a tato in combat while curie was my companion after it was taken she left and now when i go back to vault 81 to get her, i was in very good standings with her, she attacks me on sight, is this how it was meant to be?

Companions actually react to the things you do now. Curie doesn't like it when you steal. Whether this is enough to get her to attack you on sight, or if your Affinity with her was low enough that that accidental theft dropped you low enough for her to attack, I don't know, but stealing in general is something she doesn't like.