How can i gain weight faster?

So im very small.. I weigh 115 pounds. Im 23 years old. Im trying to go for 130 pounds because i feel like it and been bullied all my life. But what’s slowing me down is I have a high metabolism so it fucking sucks. Also it’s hard for me to work out because i work and go to college. Ugh and it’s hard for me to eat because i have a small stomachr and get full fast also i have acid reflux so i tend to throw up and gag..

is there a drink or something i can buy for gaining weight ???????? let me know thanks!