How to gain weight fast?

I am 19 yrs old female and i weight 105 lbs 5'3 ive been slim my entire life and im sick of it i so badly want to gain weight but its like no matter how much i eat nothing changes i was wondering if i could drink protein shakes to add on the pounds real fast im desperate, i read the calories on the labels and it would range from 500-1000 and thats exactly what i need i tried eatin a lot of fast food but even then i dont gain any weight very weird