PreMature Beats - Are these dangerous.

6 Months ago, I had an emergency visit to Hospital for which I suspected I m having a heart attack. But after several tests like ECG, ECHO, BLOOD TEST, TMT, Doctor said it was Panic Attack and prescribed me Ciplar 40mg along with clonazepam 0.25mg. From The last 2 Months I m on one single tablet - Petril Beta 10, taken twice daily. My symptoms have improved but I still get lightheadedness, breathlessness and premature beats, all of them mainly during Night. I m very afraid of these Premature beats. Whenever these occur I feel a hard beating at the centre of my chest followed by a feeling of vomiting which lasts for around 10 seconds. Till now I had nearly 6 ECGs and these beats didnt appear even once in the reports. Moreover, i m currently suffering from Cough and Cold (Runny Nose) and I noticed that their frequency have increased, averaging out to 2 premature beats every 3 hours. Am I at danger? Is my Heart ok? Or is it due to Anxiety?