Tip 2. Make Eating A Habit
Listen, I know in the beginning of this post I was sympathetic to your problem, but I am also here to say, Suck It Up. I can tell you that to gain weight, you need to focus on making your meals a habit rather than an afterthought. Your body is pre-programmed with your genetic disposition. And in your case, you have a very fast metabolism that digests and burns calories quickly. Focus on having 5-6 calorie-dense meals a day spaced 2-3 hours apart so that your body is constantly being provided with something to metabolize and build muscle.
Calculating Your Caloric Intake And Macronutrient Breakdown!