Welcome!! I agree that you may need more calories. Add in some snacks, especially fresh veggies and fruits. An apple, banana or orange.
Celery and carrot sticks with dip (like hummus). Try smoothies! Throw in some fruit, a bit of veggies and some ice in a blender. Yum yum snack. I'm going to assume you are in school (forgive me if I'm wrong. Not sure how Romania is.) so I'll suggest ...