for your height (i am also 5'7) here is the ranges:
---under 105 lbs=unhealthy
---between 105 and 120=slim/mildly thin and the "ideal" body, also still healthy. this is you, so u r just fine. most people wish they were here.
---between 120-135=medium body and healthy. most people are here and think about losing maybe a few pounds for beauty reasons.
---between 135-150=maybe a bit chubby, but still healthy. people could think about losing some weight in this range, but they don't need to technically.
and need to lose some weight.
i think u have a very good body and shouldn't lose any more weight, but not gain any more. u have the "ideal" body, already.
hope this helped. have a good day ^____^ v