Im 42 Non Smoker non drinker otherwise in good health
I don't think anyone can say for sure but could be afib or an svt of some other sort. The best way to get it diagnosed is to get it caught on a monitor. Was what you felt at the hospital the same as what you feel in the morning? If so then they should have a record of what it is. If not and you get it every morning a 24-48 hour holter may catch it otherwise ask for a 30 day event monitor which will give you more time to catch the really concerning episodes. Also, maybe ask to get a copy of your tests from the hospital and see if they say afib. Most svts of the atria are pretty harmless but afib does pose health risks and all tachycardia can cause eventual wear and tear on the heart so they need to be managed in the minimum. So question the doctor about what type and what needs to be done to either correct it or deal with it. Best of luck sorting it all out.
A few things you can try when you feel the odd or fast beating is to cough or try vasovagal maneuvers like holding your breath and bearing down like you are straining to go to the bathroom or drinking a very cold glass of water. Some get it to stop simply splashing cold water on their face. If you find you are able to get it to stop on your own it may make it less scary for you.
I do try the vagal manoeuvre that I know and the bearing down seems to work the most. SvT doesn't worry me so much. It's changing symptoms and a gp that looks at me like he has know idea what to do next.