Here’s a link from this website regarding foods to eat/avoid. There are many more articles about diet on here, just type into search box.
Anxiety is a symptom (generalised and/ or social) in adhd.
Some stimulants can make the anxiety worse, as a result some people are prescribed an anti depressant along with the stimulant drug.
I think you need to change your meds, speak to your doctor about it.
Good luck, hang in there, you are getting help early on, that’s one good thing, I’m 40 , some people are much older when they finally get a diagnosis. My advice to you would be to speak to other people with adhd about your difficulties. Don’t bother with neurotypicals they don’t get it. Find a support group in your area, or start one if there isn’t one already. You could always do this anonymously on media. When I get an official diagnosis I’m going to join a group.
Also write down all the difficulties you face on a daily basis and next to it how you are going to manage it (you could make 2 columns on a sheet of paper ) Meds will not provide 100% relief so the rest is down to CBT and making changes in your everyday life, you have to learn to manage this, don’t let it define you. Hope all that helps 😊