A few years ago I was out with friends and we were drinking and smoking. One of my friends gave me eye drops and I started wondering “What if these eye drops interact with the chemicals I ingested” and while we walked I started feeling like my heart was beating faster every second and I had a feeling of inminent death, I couldn’t breath well and even yelled to call 911, one of my friends calmed me down by saying everything was fine and it slowly went away in a few seconds. 

After that happened I haven’t felt the same, it started happening a few days after that being sober so I went to the doctors but nothing was ever found. 

This is when I started hearing it could be anxiety or panic attacks. And everytime I would go through panic attacks I would spend days drained, like my heart felt something bad was coming, that I’d die at any second. 

I had covid back in 2019 while I was living alone and my worst symptom was that I felt chest tightness and couldn’t breath well, this lasted for about 9 days and then I got over it. But like 3-4 days after I woke up with chest tightness, and it started getting worse from there, I couldn’t breath well, like I felt a weird chest pressure, and like my breath wasn’t enough to fill my lungs, my heart rate got to a point where it was in the 100s while resting for like a few days. But the shortness of breath lasted like 3 months!! 
During this time I saw a cardiologist and got an ultrasound, and scan, both came out good, I also got a ECG which pointed I had mild arrhythmias which the doctor said they’d resolve by exercising and eating healthy. He didn’t send me meds which I thought was a good sign. 

Flash forward to now, I moved alone again and I have been having chest feelings like a bit of pain, tightness, restlessness and also anxiety, but I don’t even know why it happens, at times I wonder if my heart will ever say “ok this is enough stress” and fail… 

I guess my question is was this all really caused by anxiety? How do I make sure it’s in fact anxiety? And what do I do to prevent another panic attack or any real life-threatening condition? 

TLDR: Have had panic attacks and ecg found tiny arrhythmias but how do I make sure it’s caused by anxiety and not a heart/health condition? And how do I overcome this anxiety disorder?