I have Heart Palpitations like i feel my heart missed a beat or its working very slow?

I am 26 years old Male.
240lb 5″9 tall.
I have Anxiety disorder for about 6 yearS bow.
Mostly all the time with Anxiety i have Heart Palpitations like i feel my heart missed a beat or its working very slow and it start working very fast during this i get dizzy all the time palpitations happen mostly when im laying down.For 6 months i was good no heart palpitations they went away,one week agoo i was sleeping and i heart my apartment door someone trying to open and i was scared my heart stopped and i told my self oh gosh now im gonna have heart palpitations again anddd yes now for one week im having heart palpitations i feel dizzy n tired…i had ecg done couple times nothing was find….is this something danger can i die from it..can i work out even if i have heart palpitations?thank you.
Im very scared i have heart disease.

Age: 26
Male
Medications: None