Perhaps try increasing your caloric intake by having more calorie dense food in your diet. Things like nuts (almonds, cashews, pecans), bananas, beans, fluffy breads, granola, trail mix, avocados, dates, and peanut butter are things you could incorporate into your diet for more calories without it feeling like too much to eat. You could also try gluten free alternatives, as they tend to have more calories as well.
Another thing to take notice is that carbs are good pre workout and protein for post workout. Carbs fuel you for the energy you'll burn while running and protein helps rebuild muscle after a workout. It's most beneficial to have a little protein as soon as possible after a workout for the best results. Don't go to sleep with lingering hunger as well.
If you want to be able to see progress and feel better, you'll have to change your lifestyle. Just simply "eating more" may help you gain weight, but it wont necessarily help you feel better. You have to find a balance with what you put in your body if you really want to feel strong, energized, and healthy.
Hope this helped a bit!