How to deal with mean girls?

I’m in a program at school and we have a director and one of the girls in the program was in her office talking the other morning.

I went to knock on the door (to speak with the director) but accidentally overheard the girl blaming me for something (I didn’t do) to the director.

So I left it alone until the girl came in to class the next day and said “I didn’t tell the director who it was and even if I did know, I still wouldn’t say.”

So I spoke up by saying “yes you did” and left it at that.

She pretended to not know what I was talking about, but I accidentally heard the conversation so I didn’t lead on too much.

Then, Friday, she started spreading rumors about me to other classmates saying that I’m making things up about her and literally getting them on her side.

I’m scared to go back to school tomorrow and don’t know what to do.

Do I talk to the director and let her know I accidentally overheard and what’s now happening? or just let everyone hate me for a while?