Cow's Milk allergy

Hello Ladies my son turn 1yr 3 weeks ago and i has sooo ready to switch him to whole milk, here is a litle back story he has been breastfed his entire life and never really had any problems with constipation, bloating or gassy so i never had the need to cut dairy out of my diet so at about 9 months old we introduced cheese by giving him a few small pieces of if but he immediately vomited after it, well i say maybe its too earlt some weeks went by and i brought some yogurt bites as a snack after having just a few he had a rash aound his mouth so i began suspecting something right after his birthday i got organic baby yogurt and gave gim about 2oz which he took fine some red bumps around lips but nothing crazy about and hour later he began to vomit violently and omg my poor kid was sooo sick for abour 5 hrs after he was weak, sweaty, and could not stopped vomiting. Took him to his pediatrician and ske him to be tested for milk allergy as i was going to get his 1yo blood test in the next couple of day and sure enough he is positive for cows milk level 4 out of 6 so now dont know what do as my supply is decreasing significantly and my frozen stash is getting low we have an allergist app in a couple of days but just wanted to see if there was anyone with some similar situation, im now afraid he might also have other allergies as hes never had any seefood or nuts and im afraid to try new food now.

Thanks Ladies any advice will help FTM her 🙄.