Should I be worried?

you could just have a REALLY fast metabolism. they can give you pills to slow it down. if you really don’t have an eating disorder then I dont think its much to worry about. and not getting your period because of being thin is normal, well not normal, but it happens to everyone who gets too thin.

if your doctors think you have an eating disorder just tell them (or counsellor etc) that you know you dont and that you eat enough and actually want to gain a bit of weight, that you know its unhealthy to be this thin and you arent doing it on purpose.

they could probs give you stuff that will make you gain a bit of weight/muscle, but they wont do that until they are satisfied that its not anything else.

do you eat set meals? like breakfast is a meal, lunch is a meal, dinner etc, or do you just eat when your hungry? because my sister used to just eat when she was hungry and she just sometimes forgot to eat for like 2 days at a time. shes quite thin but not 74 pounds lol. and also eating the right things could help, like people think that fast food and take out is fattening, but for someone with a fast metabolism it just goes straight through them. so eating more carbs and meat and veges would sit in your system longer and you would get more nutrients out of it. I don’t know, just wait for the doctors results. dont worry too much though, as you said your mum is thin too so it must just be in your genes. id love to be as thin as you! lol. good luck x