Am I developing something that can be detrimental?

I`ve always had a problem with the way I look. For so long I have always thought I was fat even though my family and friends try to convince me I`m not. For the past couple months my weight has steadily gone up to 160. I`m an a track team but I`m gaining weight. I always do this negative self-dialogue in my head. I`ve been eating less and less because of the comments I make about myself. I`m always unhappy. When I eat I feel so heavy and grotesque when I`m done I avoid food later on. It`s gotten to the point where i only eat dinner since I don`t want my family to worry about me. I count how many calories I eat and I try to keep it under 1000 calories.