You are "severely underweight". 2 steps below the recommended range. 52 is crazy, crazy skinny. This is what doctors use to legally classify you with anorexia/eating disorders. Dropping below 50 will classify you as a candidate for organ failure. I'm not saying you're literally dying but any doctor would make you come back next week for follow ups and tests. Just saying, it's not a bad idea to look into it. If you wrote in here in the first place you know it's not normal. I'm your height and like 65-70 and very skinny.