I'm sorry OP, it's such a shit hand to be dealt, isn't it? DS is 2.5 and allergic to dairy, egg, legumes (except soy and peanut), fish, hazelnut, Pistachio, cashew, Sesame and kiwi.
He's had airborne reactions to lentils and eggs (vomiting and hives) and gets contact hives from dairy.
I think the first year was most challenging as it was such a steep learning curve. We had to find our new "safe" foods, educate friends and family, do loads of online learning, try to get his ezecma under some semblance of control, find an allergist willing to do food challenges etc.
I was breastfeeding so stopped eating all the foods but gradually reintroduced them to my diet when he was 21 months. Weirdly he didn't react anymore and he still BFs without my diet being restricted.
We now have more of a rhythm and finding food in shops is easier. I remember crying the first time I went to Sainsbury's and every label I checked listed at least one of his allergies.
We've learned to always bring lots of safe food with us, as well as tonnes of wet wipes for wiping hands and surfaces. When we leave the house we ask our son what he needs and he shouts back "Epis!". We've also just started telling him that "you can't have that, it has dairy", or "Peppa's eating eggs but they make you sick so you don't".
I try to find food fee activities like story time at the library, swimming, some soft plays, forest school etc. Our local mother and toddler's were very accommodating and made their biscuits allergen free. Mostly, i avoid cafes and restaurants when he's with me. I've learned to always speak up when out and to leave if I feel unsafe.
We've chosen to not let him eat at restaurants for now as we feel we just can't trust all staff members to "get it", especially with the cross contamination risk as he's so reactive to even trace amounts.
We host most dinners and BBQs for friends now as we feel more in control and can relax knowing there are no allergens present.
"Parents of children with multiple food allergies on FB" is a good resource.
I think, ultimately, my top advice is to do what you feel comfortable with. Never feel pressured by friends or family, as many won't fully understand IGE allergies.
We try hard not to let DS' allergies define him. We're currently on holidays abroad and he's having a whale of a time!