i want to give up

I don’t think my baby is growing fast enough.. she’s still small and she is 3 months tomorrow.. my first didn’t grow this slow but I also didn’t EB with her I formula fed as well then just switched to formula all around. she was the chunkiest little baby. I don’t think my breast milk is helping her and it’s “suppose” to be the healthiest smh.. she eats all day long literally.. plus she has bottles from time to time (breast milk) she has plenty of wet and dirty diapers.. she was only 8lbs 12oz at her 2 month appointment..