Sexual abuse with sister?

When I was little my sister use to sexually abuse me all the time, but sometimes I liked it and sometimes I didn't want to do it. She stopped touching me when I was 10 and i was so confused and depressed. So depressed I tried to kill myself at 11 and told my mom about my suicide attempt but she shrugged it off. Now I'm so confused about what to do do. Should I tell someone about the abuse that happened? I'm afraid my sister will say it's not true or tell everyone I like it so it's not abuse. I'm also afraid my mom wont believe me because my sister and I are friends now. I feel like it's not abuse, but I always get flashbacks of it and feel disgusted. I want to tell my family, but I don't know what their reactions will be. How do you think they will react? Will they be mad?