Seems so unnecessary to me!!

I'm 5'9.5" and the BMI calc says I should be approx 165lbs. Looking at these pics (http://www.mybodygallery.com/search.html?heig ht=5+9&weight=160&pant=any&shirt= any&zphoto=Large&new=1) gaining to 165 looks like there is so much unnecessary flab!!  How is that healthy??? I mean I already have side chub at 124, I am active and healthy. Even when doctors know i'm in recovery they think I look fine. My body is functioning perfectly. Why gain so much weight when it will look so unattractive to me and look like it would be hard for me to even walk up stairs with all that pudge???

Side chub? You do know there's a reason EVERYONE has fat on their "sides", yes?

I think 124 is too low for your height, I very much doubt you have side flab. + those women at 165lbs are a great weight, I don't see any flab on them at all. They all look healthy to me. Everyone's bodies are very different, some people are naturally curvier then others. Nobody is naturally fat, and none of those women are fat. 

You weight is too small at the moment, and that means your eating disorder still has a strong grasp on you. I'm in a similar boat, but I'm aiming to get my weight up to what is good for my height, and you should do the same! 

At 5'9 and 165lbs you are NOT going to be unattractive or too fat. You will be a healthy weight, which is what you need to be. And chances are you'll not even get to 165lbs. Eat what your body needs (2,500 - 3,000 + calories), and give it time! Your body deserves it. You may naturally be a lean person & your weight could rest at 140, 150? It completed depends on what your body is most comfortable at. Keep strong & good luck! 

A given weight will look different on every individual depending on your body fat percentage, the amount of muscle you have, your bone density and where you store excess fat. You're making an assumption that you'll be "flabby" when you reach your goal weight because you're comparing yourself to other people.

It's also probably better to talk to your doctor about what a healthy weight for you would be rather than trust a BMI calculator.