weight gain pure breastfeed

Hi! sino ba dto mga mommies na premature ang baby? kelan po nagstart gain weight si baby nyo? I had severe hypertension nung preggy ako kaya na E-CS ako at my 34th weeks. Birthweight nya is 1.5kg lng. after 10 days nag 1.4kg lng sya.. pure breastfeed ako, pero gapatak lang milk ko kapag inexpress. hindi gaya nung sa iba na sumisirit. im quite worried lng kc parang d enough milk ko. ok nmn wee at poop nya but she is not gaining weight..