What To Do? 😓

I work in Retail, I’ve been in this particular store for 3 years and we were recently appointed a new manager. Things haven’t been going smoothly at all. So, whenever I ask her something or try to talk to her, she either grunts, shakes her head or nods. I try to be friendly and polite but she gives me nothing. She’s always verbal with other members of staff and having a laugh but when I’m around or even walk into the room, her attitude changes a lot. In the morning, she doesn’t say hello or anything. She’ll say it to other coworkers but completely blanks me out. I feel physically sick when I have to work. I’m so, so uncomfortable. It upsets me because I haven’t done anything and I’m unsure as to why she’s being like this.