I really really want to put on weight?

You are correct saying you do not eat enough. Not only don't you eat enough you do not eat a balanced diet. You should make a point of eating breakfast as that is actually the most important meal of the day. If my calculations serve me right you are 93 pounds. You surely need to take in more protein to balance out your diet. I am not sure what types of meats you eat but eggs, fish and lean meats are necessary as part of your diet to gain weight. If you begin a workout routine and eat small meals every several hours with a little protein in each meal you will notice a marked difference in six weeks.