What to do????

My friend at school is school cut her self, and grabbed mu scissors I stopped her. And I felt like she was doing it for attention because she went around showing everyone and got sad when people were avoiding it for it. I said some people dont want to see that or have been through something like it. She always says shes depressed. And I am here with depression, trying to be happy but feeling empty. And she gets all the attention for cutting herself in class. I did make her happy but gave up.She started to make me feel bad, what do I do?