I had a panic attack the night before my first HSC exam (final college admission exams in your senior year of high school) - my mum made me take a bath cause she thought it would calm me down. I was crying and hyperventilating.
Also I had a small handful of drug-induced breakdowns in the city in late 2013/early 2014. One of them was really bad because it was like 2pm on a Wednesday in Hyde Park (like Sydney's version of Central Park) and I was completely ****ed. Everyone was staring at me like "this kid is on his way to becoming a junkie." But they were all strangers and I'm clean now, so who cares.
I get anxiety which leads to panic attacks because I work to much. I take drugs to get rid of them. Now I can work 60-70 hours a week no problem but I think my average is about 50 hours so far this year.
Edit: Also, I have been working on meditation and breathing to clear my mind with hopes to get off the drugs. Anxiety is something we place on ourselves. I have been learning to recognize it and step back.
I had a really bad panic attack after my sister's death, I thought I was gonna die. It started in a shopping centre, and lasted on and off for over an hour.
I'm not exactly sure if I have had one before, but my anxiety has been out of control lately and I've been moodier than usual. I've been working out more so that might help.
When you think it can't get any worse, it does 
all the time