Late diagnosis/possible cmpa

Has any one had experience of having a later diagnosis of cmpa? My little boy is 6 1/2 months old and we ebf. I've had a feeling that something has been off since he was around 5 months. His poos were often green and muccousy, sometimes pooing 5 times a day, he has had blood in his poo twice, he goes through periods of being incredibly clingy and upset, he's had a rash around his mouth for weeks. I've mentioned all the above to 3 doctors and a pharmacist but been assured that it was normal. Some tests were done after the blood in the poo and I did ask if it could be an allergy but was assured everything came back normal. The rash I was told was drool rash. We started weaning and he tried milk after doctors said wean as normal. He had a small amount of milk in some potato on Saturday and by Monday am his face was swollen and his eyes puffy. A&E suspected an allergy and he was treated with piriton and monitored through the day. I've now got an appointment with our doctor on Friday where I feel I need to be pushier with getting some answers. I feel so guilty that we've maybe missed this. I've put my trust in health professionals and they've really let us down.