What should I tell her? If anything?

There's this girl that I work with that I'm starting to have feelings for. We've been hanging out more and more as the summer goes on. Going to the beach, out to eat, movies etc. Thing is, she is my manager. And at the place I work with you cannot be in a relationship with anyone that's a manager/supervisor if you're a cashier/bagger. (yes we work at a grocery store.) we both are the same age, 19. In about a month and a half she will be moving to new York to go to college to study the same thing I am studying, film. I don't know how to tell her how I feel cause I feel like it's not right. Also because last time I told a girl how I felt I was heartbroken and I'd hate for that tohappen again. I feel confident with her though. Since i started having feelings for her, and showing her this other side of me, shes grown incredibly comfortable around me, and shes started calling me different little pet names like pumpkin and other random vegetables haha. I find it kind of cute being we work in a grocery store. And i call her things right back and its continued for about a month or so. Also when she didnt want to go to a certain party alone she invited me to go with her. And she has done this other times as well. What should I say to her? (if anything??) plz help any input is appreciated. Thanks in advance.