eat every 2 hours. lots of carb and protein, moderate fats. you have to train yourself to eat a lot. I remember how I used to struggle to eat 4000 cals/day, now I feel like I'm starving if I don't get minimum 4000 cals/day.
Count calories and be dilligent about it because you think you are eating a lot right now, but I can guarantee you you're not. Make 4000 your goal, then 5000, then 6000 then 7000. Eat as often as you need to to accomplish this. You will be pushing yourself outside of your comfort zone, but that's what you have to do to grow.
I remember getting to the point where I was eating constantly all day every day, consuming 8000 to 10,000 cals a day. Sometimes it was uncomfortable yes, but I grew. I was training 5-6 days a week also, and growing.
I now am too busy to eat like that (or maybe I lack the discipline currently), but I still consume at least 4000 cals/day, and I maintain a comfortable weight currently, and still workout 4-5 days a week.
Just eat a hell of a lot more, and count those calories (also count grams of protein/carbs/fat).