I had this happen over the summer. I bought a two ounce bag and had been smoking on it for about 2 weeks with no problems. Then one night, I smoked one bowl and when I was walking up to my room, I thought there was a little girl running around my house. Once I got up to my room, my heart felt like it was about to come out of my chest, and it felt like I could barely breathe. It also felt like there was something lodged in my throat and it was burning, and that wasn't good. I started puking and had pins and needles covering my entire body. Interesting experience to say the least.

Anyway... don't sweat it. It's a panic attack. If you keep thinking and worrying about it, then it will happen again. If you let it go, then you can keep toking safely.