Im incredibly small for my age even though i eat a lot and do workouts
Despite my more than enough diet im still very thin and its really an issue for me.
Are you sure you're eating enough to gain weight? Using myfitnesspal I realized I didn't eat nearly enough and I'm not skinny really.
There's not enough information for me to recommend anything other than that you should review how much you are eating each day. It depends on your age as well.
I'm on a bulking plan this month and am eating 20 calories per pound of bodyweight. The daily macro ratio is 35% protein, 50% carbs, 15% fats.
I'll put a link on here for you to check it out, its a fully researched meal and workout plan for February.