Hi ,
I hope I'm not replaying too late to help.
If a PB&J sits well with you, I would absolutely bring it. And bring any safe foods that are easy to pack so you have snacks. I would try hardest not to eat new foods as you don't know how you will react to them.
If you can, get an aisle seat on the plane so that you can access the bathroom easily.
Make sure you pack extra underwear and even a set of leggings in case of the unthinkable. Always have wipes in your purse too. I always keep Peppermint Essential Oil in my purse as well, because it calms a spastic colon and it works wonders on me.
Arrive to the airport with plenty of time so you don't have to rush and get unnecessarily stressed.
Also make sure you hydrate and have water with you.
Hope this helps some!
Elizabeth (team member)