Hardgainer here :) 34kg :S

Hi there, new member here. I found this site when I was lurking around Google for tips on how to gain weight. Well as you can see here, I'm 19, 5'1 and to be frank I lost about 1 kg after 3 years of maintaining the same weight which is 35 kg. I'm not sure what is wrong with me actually. I've consulted various doctors but to no avail. I've done medical checkups for 2 times and they told me I have no thyroid problem, everything is normal. However, I do have bronchiectasis (small damage of bronchioles in my lungs) and I'm not sure if that affects everything. My period is not regular because I'm underweight. Well here I am, where I decided to register to this site and learn everything I can to gain weight the healthy way. Hello everyone!