So tired of being Slim Ive tried accepting it but I rather be bigger

All my life ive been small like this and now im 21 and im tired of it I want my life together and I wanna feel happy with myself. I feel so unaccepted and not as attractive as other girls because I  have no curves. I am getting comments like ur perfect gurl great personality but if u were 20 pounds more I would have to be with u but because I am not im passed over. This has really gotten old. I have gained once in my life and thats because I was on birthcontrol now I havent been on it in over 3 years because I no longer date men I have lost all the weight I had from 5'6 126 pounds 34c to 5'6 118 34b and thats a improvement bc I was originally 112 so ive been working on it. I want to be a healthy weight for once. So anyone with good ideas I would appriciate it a lot. I want to gain 20 pounds!

Hello!

 I know how you feel.  I have been thin my entire life and have always hated it, too.  It was especially hard from around the age of 14- my early twenties. 

I am sorry I don't have any great tips for how to gain weight, since I am still trying to do so myself, but I just wanted you to know that I understand and you are not alone!