Hi lil, I hope you are feeling slightly better. Sorry for being slow in a response, I don't come on MN everyday.
How you are feeling sounds just like what I was going through last year when my DD had her first anaphylactic reaction at 9 mo. I had frequent episodes were I felt like in was having a panic attack and felt so overwhelmed, and also in floods of tears. I also had lots of times of feeling really angry about 'why my DD, why can't she have a normal life, it's so unfair.' But it really does get easier. I think the first few months of clearing out your cupboards and working out what products and brands are safe was the hardest. Once you get into the habit of reading labels it's not as difficult as it is to start with.
There's already great advise form the lovely MN group. Do go down to personally speak to your DD's preschool and take an action plan like from anaphylaxis campaign. I found their online workshop for allergies really useful, especially from my dd's nursery plan. They mention things like advising against using cereal boxes when making things because most contain nuts. Make sure whoever is responsible for your DD is epipen trained and has annual refreshers. Your practise nurse or a community nurse can go to them to train them.
Please do take one day at a time, I remember thinking the same at how it seemed impossible, and is till do that now sometimes, but just step back and concentrate on now and tomorrow.
Also really go through the signs of anaphylaxis for yourself and your partner, because I wasn't aware until going on a workshop with the anaphylaxis campaign how seemingly mild symptoms like an unexpected hoarse voice or unexpected persistent coughing is an indication to use an epipen. And always remember and also drum into the preschool staff, you cannot do harm by using an epipen inappropriately, but you can by not using it when you need to. They are amazing, I've had to use my dd's epipens 3 times this year and they work so quickly, it's really reassuring to know. But it really helps to know all the allergies which we have only recently finally got answers to (DD is now 18 mo) so you will feel better when your DD finally gets all the tests done.
Anaphylaxis campaign is great, as is MN. Real life people are so variable at their understanding and support, even family can take a lot of persuasion. So ask away anything you like and hopefully each day will get easier. It is a hard first few months but it honestly does get easier. You learn to plan everything and take food with you everywhere, that includes social occasions like parties. And if you think it's too risky, just avoid it the situation until feel kore confident, your dd's health is more important than worrying about peoples reactions. Do show people the epipens when explaining things, for some reason that makes people believe you more.
Sending lots of hugs and hoping you are all doing ok. :)