OMG! I'm so sorry that he is having a hard time. My daughter also has allergies but, hers are not severe. She does not have to carry an eppi pen because her allergies to peanuts is mild. She will break out, get very sick, have diarrea and things if she does come in contact with them. But it is a challenge I have not had any problems with daycares though, most daycares are peanut free around here and take allergy children's regiames very seriously.
My daughter was tested just before she turned one and found she is allergic to whole milk, eggs whites, soy, and peanuts. Her number for reaction to these were low but did disrupt her digestive system. She would projectile vomit whole milk and when she was an infant I breastfed her but had difficulty when she came home from the hospital and tried to suppliment with formula and thats when she had her first projectile vomit of anything other than my milk. Anywho I can go on for days...
So bottom line she is now two and has outgrown the reaction she has to the milk, she really does not like milk at all, but i can cook with it and she does not have a reaction and she has a bit of it in her cereal and does not react. She can now eat eggs when they are cooked, but not raw, she cant eat things like mayo, or things containing egg whites that have not been cooked. She cannot have soy sauce or things that contain like...well its hard to explain, lots of beans and peas are soy based so we try to avoid them, the thing is if she does have them she may or may not have a reation, with the soy allergy if certain foods containing soy are heated to a certain temperature it breaks down a compound that she has the reaction to and changes it so therefore no reaction, so a lot of box food that contains soy she won't have a reaction to. Weird I know! The peanut allgergy although mild compared to your child is the one I go to great deepths to avoid the most. I can't tell you how many times I have had to walk away from fast food joints because they cannot tell me if the fries are cooked in peanut oil, you'd be surprised some still do and really watch the mom and pop food establishments because they use it the most. I am going to have her re-tested soon because she has not had contact with peanuts and I want to know what her numbers are and see if the allergy is better or worse and if she needs an eppi pen. Last year she came in contact with some cereal that had peanut flavor and she had a reaction but her breathing was ok, when she did have peanut butter once thats when she broke out really bad and had shallow breathing and was really sick and ended up in the ER they had no clue what was wrong with her and sent her home to suffer they did give her benedryl though two days later I had the results to her allergy test.
The things I do to adjust are:
If I go to friends houses or restaurants then I pack her food and take it with me.
If it is a last minute trip to a restaurant I let them know she has allergies to food and order her fresh fruits and veggies, letting them know will usually help them be aware of cross contamination when preparing her food. Although don't expect a miracle since your son is very sensitive. preparing the food and having it with you is best.
I always keep containers of applesauce or mixed fruit in her diaper bag for emergencies.
Maybe try keeping some gerber prepared meals for toddlers handy so you can grab it when going out on the weekends just keep it in your car just in case. I use to keep a lot of food in her bag so she always had options.
Planning is how I get through, & reading, reading, reading...I didn't find it hard to adjust, just frustrating when others didn't ask and would just give her things to eat (extended family) they'd tell me things like well i didnt know, even though I was in the other room and they can ask me if its ok, also they would say "well she wanted it!" Then I was left taking care of a sick baby. I had to be very watchful when around other people, I'm much more relaxed now but that was the hardest part.
I also put on her diaper bag, using a luggage tag, a list of her allergies. It is very hard to leave her with other people for long periods of time like overnight or all day when they are not understanding of her allergies you will have a select group of friends you will leave him with and trust to make the right decisions with his food. You will find it harder to leave him with friends who have other children because he will have a greater chance of being exposed to something, even dust mites, like a child might share a stuffed toy, or blanket that is infested and he will have a reaction. You will find it better to leave him with friends who don't have kids or pets and just have one and are attentive. the another poster said you will learn who your good friends are and that is correct.