how do i up my milk supply quickly

my daughter is 13 days old. when my milk first came in i had enough to pump after she ate, now she's having a hard time latching and staying latched. im still latching her trying to get her to suck/nurse for 25 -30 minutes , and pumping after shes done eating, and giving her the milk i pumped. ( im trying to help her gain weight, we are seeing doc often for weight checks due to her nit gaining weight like she should) and now my milk supply is going down quickly. my breast arent even filling up by the 2 hour mark. i dont know if its due to me stressing over her weight, or what. but i know im giving alot of effort to keep her trying to stay latched, and still pumping after each nursing session. im trying to keep lots of nipple stimulation, and im drinking mothers milk and using gound fenugreek in my food . please help...