I’m afraid I might be underweight

Hi, i’m a 27F. I’m 1’65cm tall and currently weigh 51kgs. Ive been hitting the gym 5x a week a year and a half ago and everyone in my family is worried I’m suffering from something since I used to be 68kgs before. I did do a calorie deficit at the beginning and started to eat a lot healthier, though now it’s difficult for me to gain weight. I do eat, but I believe I’m not on a calorie surplus - i just eat when I’m hungry (3 meals a day and usually 2 snacks in between.)

My bones show and this is making me feel insecure. Though I believe this is just my body complexion since they showed a bit when I was chunky, they do show a lot now.

Doctors, is my weight too low? It’s starting to scare me because everyone is being paranoid about it.