How bad is my eating?

I keep between 300-600. I'm 14, 5'4 and 89-91 pounds. I really watch what I eat because I'm absolutely terrified to be made fun of my weight. I throw away my food any time my parents turnaround. And when I'm completely starving, I eat something but then I spit it out. I also take laxatives. But I don't make myself throw up. Today, I've eaten cereal with soymilk. I don't think it's as bad as people assume it is. I used to be 5'2 and 110 pounds. A ton of parents from my school have been giving me lectures about me being too thin but I'm sick of it! I don't even listen to the lectures anymore. I play volleyball an hour a day and sometimes I go jogging. I'm in track at school. I just want to know if I have an eating disorder or not. Thank you! c: