Sensitivity or allergy

Patient: When my son was born he was on formula but he had a bad allergy or sensitivity to the formula…he had horrible gas, was very fussy, vomited after each feed and had blood and mucous in his stool which led to bleeding sores on his bottom. we went through many formulas even the hypoallergenic kind. when he was 3 months old i relactated and have been breastfeeding ever since. after he was on breastmilk he had a strain of rashes that we corected by switching diapers we like huggies best. when we started solids at 6 months old he never did like the baby cereals. he would eat fruits vegi’s and meats with the worst problem being gas but he was breastfed and didnt eat but a few bites of whatever he ate.he is now 13 months and i was worring that he wasnt getting all he needed from just breast milk and all the few bites here and there through out the day. so i have been trying to push solids…i wanted him to get more of the foods that i was eating. i didnt realize but looking back i can see the newwer foods i was giving him were lots of grains: bread, crackers, cheerios, noodles… he has been very fussy with tummy aches, hes always sleeping on his tummy and tossing and turning and whines in his sleep, and this morning he had a very runny and mucoussy diaper…and his diaper rash is i researched this and i found a posting saying that babies do not make a certain enzyme required to digest grains until atleast 1 yearold and up to two years oldi dont know that i trust this article as it doesnt show any research! or evidence that they are telling the truth?what could be wrong with my son?also i do have a doctors appointment for him are there any tests i should ask for or questions i should ask when at the doctors? iam worried that he will have food allergys or sensitivities? what should i be feeding him until the appointment?