making more breast milk

Cynthia • 22 | girl mom 💕
what did all of you use to up your breast milk supply? i'm getting over the stomach flu, where i couldn't even keep down water, and it affected my milk supply tremendously. 
i've tried using another mothers milk cause i'm not making enough for my baby, and i've already tried formula. she didn't like either one of them and spit them both up almost immediately. 
i'm getting desperate :(