Firstly, there is no need to worry if you are skinny. It would be nice if you know your weight in relation to your height, so that a proper evaluation can be done. However, as regards your question about gaining weight is that you can simply continue to eat a healthy diet. Pay attention to health concerns, if any. If not you can be rest assured. Remember, the more you worry the more it will create health problems.
Next Steps
You can consult a dietician for a healthy diet plan. My suggestion is that you increase your daily intake of complex carbs, like whole grain and protiens to ensure healthy weight gain. Eat at regular intervals, carry snack boxes. You can have fruits, bananas and dry fruits regularly.
Health Tips
Avoid binge eating and worrying too much about weight problems. Avoid junk food and sweets, focus on healthy weight management. Every person has a rate of metabolism. Aim at being healthy, active and strong to be able to focus on your work and other activities.
Sleep well and stay away from the worries of the day.
Get involved in activities you enjoy doing and spend quality time with your family to keep you fit in every way.