How to gain weight while eating healthy?

Im 16, a junior in high school im about 5'9" and weigh about 130-135 lbs. I workout everyday and though i do steadily see more muscle tone im not gaining weight and I just still look scrawny. I eat a lot all the time and can't seem to gain weight no matter how hard i try...I generally don't eat that healthy so i don't want to start eating more junk food...so my question is, Does anyone have advice on how to gain weight in a health manner?