How do I gain weight?

Victoria

I lost around 10 pounds recently because I’ve just not been hungry. I’m 5’1 and used to be 100 pounds but am now at 90 which isn’t exactly healthy for my height. How do I gain this weight back without feeling nauseous from overeating? Ps. I don’t think I have any type of eating disorder that has to do with body image as I’ve finally learned how to love myself for who I am :) I just want to be healthy and at a good bmi