Panic Attack

I've never had a panic attack before, but I had my first two today in school.
It was so scary. My first one happened in class while I was taking a test. It was completely quiet until I heard this huge bang. I immediately thought the school got shot up. Then I started worrying, I felt a shiver run through me of panic and then I calmed down.
The second one happened during our pep rally, I'll be completely honest here.
I was scared that I'd be siting up there on the bleachers without my best friend. I felt like I was going to die or kill myself right there. All of the sudden i have these goosebumps and I can't breathe anymore. I start to hyperventilate and I felt very faint. I felt like I was going to either pass out or throw up.
I tried hard to focus hard on something else but it wasn't working. Luckily my best friend showed up and I calmed down... I was so scared.