I have failed 😭

Today my 2 month old son was diagnosed with FTT because my breastmilk is not providing him with enough fats to gain weight, she suggested i breastfeed him and provide an extra 2 oz of formula every 2 hours for the next 2 weeks 😭 just as i thought we were doing well and then this happens. I was unable to breastfeed my first at all because my milk was toxic and now this with my second child..... Feeling like i was never made for breastfeeding 😥