I was in the same boat il explain how i am slowly getting out of it.
1 probable factor is im nearly 25, and my motablism isnt as fast.
I bought a bench and 60kg of free weights.
I train everyday, 1 day back 1 day front, with a friend (uni house) 3 rounds or max 10 reps. (it may not be perfect but i find it comfortable, and have been upping the weights regularly, id say i bench 6kg more now per arm that i did when i started.)
I eat breakfast, normal lunch, and large dinner, but i also drink a large carb/protein mix equivelant to another meal, after each meal. (drink fairly heavily too)
Progress so far in 2 month is a stone, and noticeable upper body gain.
6ft2 12 stone and gaining.
Because i was skinny, i have a low body fat ratio, probably an unhealthy one, but i sure look toned.