I was once hitting 2 pipes of AK-47 at the same time, took like 4 rips off of each pipe. That was a mistake. I thought I was going to have a heart attack, couldn't feel my body, everything felt super slow and I couldn't move. That was the highest I've ever been, was a horrible trip, but yea everything turned out fine. Basically the way I look at it is if I'm high my heart is going to be beating fast, if I start getting paranoid it's going to beat even faster and harder. Just gotta chill and you should be fine. I hate bad trips on weed, I've had like two.