Am I showing early signs of an eating disorder?

I am currently classified as obese. In the last 8 days I have lost 6 pounds by restricting my calories and have begun to exercise (definitely not excessively). Each day I consume less and less calories. Today will end with me consuming 500 calories. I am afraid to eat because I worry that it will impede my efforts to lose weight. My rationale is that as long as I eat some healthy things throughout the day I will be fine. My sister was anorexic several years ago and I am nowhere near where she was. She was underweight, losing her hair, wouldn't eat at all, denied she was hungry, would exercise like crazy...my fear is that I have started on her path. Though it will be several pounds out for me to even move to the "overweight" class something doesn't feel right. I have a "cheat day" where I eat what I want, but I am even afraid of eating then. Does anyone with more experience with how anorexia starts know if I'm in danger?