Is being 5'9 and weighing 123 pounds bad?

I don't want to freak my boyfriend/ our friends out if he sees me in a swimsuit on spring break.

I'm not really skinny, but you can kinda see my ribs on my back and my hip bones are really hard. I'm scared it'll freak my boyfriend out because his sister struggled with weight problems and I don't want to make him worry that I'm on that same track. I'm like this because my ADD medicine curbs my appetite and I don't eat much, I went from 142 in September to my current weight. Do you guys think I should try to change my weight?
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+1 y
That's about 56 kilos. A few of my friends are around 5'3 and weigh 76 kilos, it's another reason I'm worried.
Is being 5'9 and weighing 123 pounds bad?
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