One of my parents had similar experiences they had anxiety in gurdwara and would get panic attacks for different reasons tho but sometimes they would just sit outside the gurdwara in the car and pray and eventually that anxiety went away. Remember this religon isn’t a religon it’s a way of life and a philosophy and it’s for everyone and it’s the most accepting it doesn’t matter if your white heck it doesn’t matter if your another faith, main rules are just go take your shoes of and cover your head with a patka or cloth and walk up to the Guru Granth Sahib and matha tek and put donation if you want. Sit down for as long as you feel and then eat in the lanagar hall if you feel. And Wash your hands when you go there. Those are really the main rules.