Why can't I gain weight?

Im 19 years old an I weight 110p and I hate bein little I havent always bein this little but now that I am I really im unhappy I try to eat everyday but I cant sometimes an I dont unnderstand why what am doin wrong?

Eat regular meals, concentrate on healthy carbs & make sure you eat enough protein. One reason vegetarians are skinny often times is their lack of protein - meat, poultry, fish, beans, etc.

And, if you aren't, do some cardio exercise (moderatly) and do a lot more anaerobic exercise, as those exercises that build up muscle will be more beneficial to you for weight gain.

Last, if you don't already take some protein shake or similar supplement, start taking one, but only in conjunction with exercise, else you might just bulk up on fat. Back when I did a lot of weight training, I had to take "mass building shakes" to help ensure I was consuming enough calories.

your body can only absorbe like 90g of protien a day so dont eat too much. try donig research on "complete protiens" rice and beans. peas and carrots. egg whites. dude I had the same prob.. I ate like 16 times my weight a day and worked out all the time and nothin. I guess the only advice I can give is learn before you do anything. make sure you are doing your workout right and eating correctly and everything that ties into it. dont get frustrated and take supps and steroids because those will just make the issue ultimately worse