I got a panic attack for the first time today and i genuenly tought i was having a heart attack. My friend rushed me to the emergency room where i was able to calm down. The doctor said everything was ok with my heart and that i just experienced a panic attack. And now im kinda scared of falling asleep cause i constantly think what if the doctors were wrong and what if those were heart attack symptoms and what if i die in my sleep cause of that? A large part of me probably thinks im just anxious but i cant help the feeling... What can i do?