Milk production sudden drop

I was producing a great amount of milk and am exclusively breast feeding. Last night I noticed I might be getting mastitis in my right breast and it seems to have subsided. However, now my milk supply in both breasts has dropped significantly. My baby is so incredibly fussy and I am so frustrated because I can't give her what she needs and my SO doesn't understand my frustration. I am drinking the tea that is supposed to boost milk supply. It hasn't worked apparently. Please help