Slow weight gain HELP

Sa

This is gonna be a long post I appologize in advance!!!

So my daughter is 5months and 3 weeks almost. She has had quite a few little challenges already, bad reflux, tongue tie that caused me to lose almost all of my supply, allergies, and cow's milk protein colitis.

She has been on a medication for the reflux since about 1month and she got her tongue tie clipped at 2 months.

All of these things have affected her weight gain over the months so she has been on the lower end of the scale. She was born at a whopping 9lbs 3oz (95%) but her percentile has been dropping ever since. Now she is like 28%.

I am breastfeeding and have cut all her allergens out of my diet, and she has been on solids since 4months +1.5weeks. (Yes I am aware that the general recommendation is no solids until 6 months but in her situation the allergist recommended early introduction in the hope of preventing her from developing more allergies). She has been getting a small amount of solids once a day. The pediatrician said only give them to her 1x daily until she is 6months, then we can increase it to 2-3xdaily.

UNTIL her last visit on Thursday where we weighed her at 14lbs 9oz. She only gained 1/2 a pound in an entire month so the pediatrician said she was pretty concerned about that and recommended increasing her solids to 2x a day right away.

This girl breastfeeds pretty consistently every 2 hours through the day AND probably every 2-4 hours through the night.

I do not understand how she isn't gaining enough weight.

My milk supply feels really strong so I don't understand what is wrong that she is gaining so slowly now.

The only solids she actually likes is fruit and sweet potato so I don't see how that is really gonna help her gain more weight. I'm trying more veggies and meats with her but she doesn't like them so I can only get 1-2 spoonfuls in and then she refuses. She also eats rice cereal but that is pretty bland.

Does anyone have any suggestions or tips? I'm not sure what else to do.