You would need a therapist to get a diagnosis and help, but you can learn grounding techniques online or asking around.

When anxiety hits me through sensory triggers like loud noises, bright lights, colors (think of a supermarket)....it’s like I get immersed in a sea of derealism where everything doesn’t ‘feel” real, So I pick up an object and focus on it reading the label, reading the ingredients, looking at the contents ignoring my environment till the feeling goes away.

Sometimes a splash of cold water helps, are a sharp slap against the arm or leg,...anything that can pull yourself up and out of the dissociative distress.

Call around to mental health clinics and ask if they offer such a system.