Another panic attack

It's 3:29 am in NY and I just had to get out of bed because my heart was pounding out of my chest!!! I can't stand this!!! It's killing me. I really don't know what to do to fix it. I was sleeping fine and then I wake up and I'm feeling my chest because I can feel my heart beating so hard that it's vibrating my chest and stomach and it's really nerve racking. There were no bad dreams and nothing went wrong today. I layed down feeling like I was gonna have a great nights sleep I really did. I just want to cry. What is wrong with me. Is this Ptsd? Some heart issue ? Health problems? I need an answer to this so bad. I looked at my phone and it said maybe I didn't drink enough water the day before and that may lead to rapid heart rate while sleeping. I just don't know. I feel like my parents are healthier then me. I feel like everyone is happier and healthier then I am. What did I do to deserve this? Anyone out there have this problem too? I've been to doctors and they say my heart is fine!!! What am I just hyper sensitive to changes is my body or something???? Please if you have what I have let me know. Tell me what you do about it. Thank you guys.