Please find a Cardiologist specialized in obstructive Hypertrophic Cardiomyopathy (oHCOM). He must do a full echocardiogram or another test to see what is going on. It is true that anxiety can make things worst. Try to remain calm and take action. I had similar symptons in the past as you have. How is your blood pressure. Is it in the normal range or not? How is your pulse when you are sleeping at rest. There are apple watch you can wear that can take your pulse while you sleep. Is your diet healthy ? Is your weight healthy? I eat half of what I used to eat and only fresh vegetables with limited amount of fish or chicken. No deep fried food or fast food at all like McDonalds, or similar no no no. Do not eat french fries that are deep fried either or salty. Now I take slow walks every day to control my weight and high blood pressure. AVOID STRESS.
The key point here is find a highly specialized Cardiologist with at least 10 years of experience. If you have trouble finding one, give me your zip code where you are and I can find one good one for you. If you do not eat healthy low sodium diet ask your doctor what is the best diet for you and follow it. You are young and strong and you can do all I said. I am almost 65 years old and if I did it, you can do a lot better than me. God bless you!