Panic Attacks & Arrhythmia

I'm in a scary position. I went to the ER on Valentine's Day, a little over a month ago, for the first time in my life. I worked at a coffee shop, I vaped, & I was manager. This might not make sense yet, but it will later. I went to the ER because I thought I was having a heart attack. My heart felt like it would stop (that or it was beating so fast that I'd lose feeling of my pulse), I thought I was going to d*e, I struggled to breathe, my chest and left arm went numb, trembling, sweating, my hearing went away for a second too, & ALL OF THIS WAS HAPPENING WHILE DRIVING OKAY. I started to panic.

The struggle to breathe & being unable to find pulse happened a couple times before this attack whenever I'd vape. Turns out I would ingest caffeine & nicotine everyday, which are two big stressors. Plus being manager, working a double on Valentine's Day w/ my boss breathing down my neck, caused even more stress. So my body was under an eminence amount of stress already.

What makes matters worse, is that while at the ER they tell me I have Sinus Arrhythmia. My heart doesn't keep a steady beat. & I'm putting all this stress on it. Being an anxious person, I stress about my heart while at the ER. Ultimately, they gave me anti-anxiety meds, & I had a blast watching the paintings in the room move around the canvas's.

Now, I struggle with the aftermath. I constantly worry about my health/heart. Which makes me panic. What do I do?