Bulimia?

I'm not extremely heavy, but there is fat on my body, and Im extremely insecure when wearing a swimsuit. My parents are constantly concerned about my weight, which scares me even more. I know everything that's wrong with making yourself throw up, but i've been constantly thinking about doing it. It's all I can focus on, and I can't stop until i try. I haven't been able to, and I got so scared that Iconfessed to my mom. All she said was that it's ok that i'm experimenting but not if I do it constantly. I really don't know what to do! My therapist has reccomended a nutritionist but I'm scared and want to lose weight fast.