Why do I look skinnier than my weight??

I'm 48 kgs (106 lbs) and 159cm (5'2) but I look sickly thin. My face is sunken and I can barely pinch any skin from my body. Everyone guesses im 40kgs (88lbs) and below ... On paper it says my weight is perfect for my height but I don't see it and I definitely don't feel it. I don't feel good nor healthy at all. If anyone has any explanation or can relate to something similar, please share it with me.. I know this is a sub about working out, i don't work out but I couldn't think of a better sub to post this to...