Hi Anne,
Only a medical professional, after appropriate evaluation, can determine the presence of a true eating disorder.
I am also 5'1" and very curvy. For me, 100# is a bit too thin to be healthy, I do better between 105 and 110 (though, I gotta admit, at this "old age" I'm at now, I've shifted more towards the too heavy than too thin

)
A word of caution here: skipping meals CAN make you gain weight! Weird, huh? It is true, though. When you skip meals, your body freaks out and thinks you're starving it, so it STORES (as fat) alot of the calories it receives instead of burning it off. The QUANTITY of food you are eating daily may or may not be adequate (check your caloric intake), but you will maintain and/or lose more readily if you break it up into smaller meals every few (2-4) hours. That way, your body is satisfied that you're not going to starve it, and will burn calories more efficiently.
hope this helps,
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Copper
Let Miracles Replace all Grievances