School Play

I am the mane role in my high school play Romeo & Juliet and I suffer with anxiety and minor depression, i really don't want to perform in front of lots and lots of people but I feel like I have no choice. I volunteered myself for the role but now that the show is coming up I just don't think that I can do it. Since the previous Juliet said she didn't want to do it I feel like she will get mad at me if I don't. I don't know what to do... Help please