unlike what many would tell you about eating, over eating will not make you gain muscle, it will make you gain fat and you will think that you got bigger but it is fat....and fat can slow down the process of gaining muscle. the most intense workout you can have will make you consume at the most 400 Kcalories but in general it is much less than that.
unfortunately some people gain muscle faster than others but with some more time you can compenstae.
this is what i suggest you do;
1- watch your diet there is no need to wolf down anything you see, just eat normally concentrating on adding more protein to your diet.
2- put down a good routine and make your workout short , maximum 1 hour
3- lift slowly with 10-15 reps no need to go heavy, but you need to concentrate on contracting well and extending well your muscles, at your 10th rep you should start feeling the burn. But Do not make each and every workout intense , just work hard every other session for each muscle group.
4- rest well between workout. a muscle must rest at least 48 hours after a workout.
5- stretch for feww minutes after a workout
6- You can go heavy and low reps every 3-4 weeks for each muscle (6-8 reps)