I was deathly skinny at 155 pounds about a year ago at the same height...i can only imagine another 15 gone.
I have been in your shoes man, i was a fatty after high school and dieted down to extreme lows because "a low weight is better than being fat"... I now sit at 190 and am still gaining.
Protein powder wont do anything...ANYTHING...for your physique. It isnt steroids or supplements, merely powdered food. You might as well have said "I started eating chicken breast". If you want help from someone who has been there, PM me and i will do what i can.