it stays in your system for about 30 days. I used to smoke, its not a habit you want to start. Its way more habit forming than people like to admit and it is harmful to your health as well as your life. I don't think you had an allergic reaction, but maybe it was just a shock to your body or like the other person said, maybe it was laced. I didn't have any of that happen to me the first time, but I was already smoking tobacco, so maybe its just your body reacting to the smoke in general and not the drug. DONT DO IT AGAIN and if you smoked it with someone else tell them not to as well, if they dont ts easier for you not to hang with them anymore, you dont have to be enemies, but you dont have to be around when they endulge in that habit!!!