Gilla, tea and coffee are a no-no for a low histamine diet. You might want to check out the list of foods and be sure only to eat foods that score zero/green for at least 2 weeks:
https://www.mastzellaktivierung.info/downloads/foodlist/21_FoodList_EN_alphabetic_withCateg.pdfPeppermint and chamomile tea is okay. That's about all...
Milk is fine, as is any fresh dairy - including soft cheese, ricotta, mozzarella, mascarpone - but no mature cheese or any other cheese really. It will be a lot if you want to rule out gluten, dairy and be low histamine all at once - but possible!
With nut milks, almond scores a 1 on the histamine chart so should be excluded for the 2 weeks as well. Not sure if any dairy free milks are also low histamine, you'd need to look that up.
It has taken me a week to learn about what I can and can't eat, I haven't even been shopping for it all yet. It is a very restricted diet if only eating 0 scoring foods, but I think that is necessary to get an accurate diagnosis... If you feel much better you can then experiment to find out what your threshold is and how much of what you can eat and be a bit more experimental. I know some people drink coffee for eg, and are okay - as long as they don't also at the same time eat other high histamine foods. It will all take some practice, but IMO diagnosis accurately is the most important thing to start with and to do that you need to be pretty strict.