Like someone said before, your addiction may not have anything to do with your wight unless it's stopping from eating.
I used to be very skinny too, until I got really tired of it and decided to change, to be more healthy and better looking.
You probably thing that you eat a lot (most skynny guys think that) but you really arent eating enough, you're burning more calories than you consume, so here are to roads you can walk. 1. you can just eat more (of whatever) ,or, 2. you can eat clean, sing up to a gym, and get big.
if you decide to go with the second option. start by eating right. calculate 1.5gr of protein per kg of body weight and do the same with the carbs. try eating 5 to 6 times per day.
there is a lot of info on this matter that you can find online.