breastfeeding

my daughter is 3 months old and is ebf. but i just dont think i can emotionally handle breasfeeding anymore. knowing its all on me no help its starting to drain me emotionally and mentally. i love breastfeeding but its just gotten hard. we think shes lactose intolerant and its soooo hard to to eat dairy free. i just feel so guilty even thinking about going to formula. she's 3 months old and only 9lbs 11 oz. she's so little and only at the 2 percentile for her age. the dr isn't worried but i am. i feel like im failing my daughter if i dont formula feed or if i just keep breastfeeding. I feel stuck 😔