Sudden palpitations. Wrong with me?

Hii, I was diagnosed with panic disorder 3 years back but now it's under control, but since a month I have been having some panic attacks with lightheadedness and feeling that I will faint and some palpitations. Yesterday I had a lots to drink and I was hungover, at night I got this feeling in my chest that my heart skipped a beat or the beats were very unusual like two big thumps I woke up and my heart was racing a bit. I had no other symptoms just a bit chest tightness. Something similar had happened before I did go to the doc they did ecg and tni test or something but it came normal. I'm 26 years old 5'11 and 74 kgs. Very healthy I gym at least 3 days a week. All my other reports were perfectly normal including the lipid and liver, kidney thyroid and so on. So is it my anxiety or is something wrong with me? I can control and handle all panic symptoms but the heart thumping is a nightmare.