Whether or not you are at a 'healthy' weight, you notice and feel that you are having some troubles with your body image, and eating habits. Not eating for a few days and then eating a whole pizza then throwing it up is not something you should 'deal' with alone. In my opinion you should seek medical advice, which is scary on its own, but then again, if this develops and continues when you are older, serious help problems will follow. I know you're embarrassed, but you don't need to be. Maybe do some research on the computer to find a medical center near you or something close that has some support and information of things pertaining to this. I have had severe body image issues when I was an adolescent and are embarrassing as it is to admit to, I tried being bulimic and controlled what I consumed, and I would starve myself just to feel better and attractive. No matter who told me I looked fine, I was my worse critic and constantly looking at myself in the mirror made me dedicated to unhealthy change. It isn't something to be embarrassed about, but the nervousness is understandable. But still, your health will be affected by your eating habits, whether or not they stay the same (or get worse). You will start to feel better and maybe someone who has gone through the same things you can find to confide in and be open to advice on how to manage this. Best of luck, and I honestly wish you strength to face your image troubles. Take care!
You should definitely see your doctor about this. Eating disorders don't just up and go away for most people; it's a lifetime battle. Society, TV, magazines all help to give you the "Perfect" image of what you should look like, unfortunately, it's not the "norm". The fact that you can even admit there is an issue says a lot about the mature person you are becoming. That same maturity will help you and lead you to get help. take care