Heart Beats Fast and Things Go Dark, But the Doctors Can't Find Anything Medically Wrong
It sounds like you may have a bit of underlying anxiety or panic. Do you find yourself having these episodes when you are in a stressful or overwhelming situation? The episodes you have described have been at school, which can be a stressful environment (especially in high school), as well at a concert, which can be loud and overwhelming with many people and competing loud noises.
Panic attacks occur with abrupt onset and some of the symptoms of panic include what you have described: your heart can feel like it is beating really fast, you may feel dizzy, light-headed or faint, short of breath, and a feeling like you are not sure of your surroundings (derealization).
It is great that you have discussed your concerns with your family and that you were evaluated by a cardiologist and a neurologist, as these symptoms can sometimes mimic those seen in heart disease, thyroid disease, and some neurologic conditions, and it can be very difficult to differentiate.
Having anxiety or a panic attack is nothing to be ashamed of, and is more common than you may think. You may benefit from speaking to therapist, such as a clinical social worker or clinical psychologist. They can help you realize what brings about these episodes and some ways of coping with certain triggering situations so that you can avoid having these episodes. Additionally, you may want to try some relaxation techniques, such as yoga, deep breathing, mediation or aromatherapy.
TeenHealthFX is unsure of where you are from, but if you live in northern New Jersey, and need help finding a therapist, you can call the Access Center from Atlantic Behavioral Health at 888-247-1400. If you are not from northern New Jersey, you can call your insurance company and find out therapists or psychologists in your area and are in-network. Additionally, you can log onto the US Department of Health and Human Services Substance Abuse and Mental Health Services Administration website for referrals in your area.