Experienced same effects a couple months ago. After first 6 hrs my partner and I decided the stuff wasn't right. Along with how we were feeling, it burned to quickly and scorched far too easily. We have enough experience to rarely have any black stuff in the pipe and we use torches, not lighters. He felt sleepy but restless and I was very edgy, anxious, annoyed at everything kind of like a bad comedown
after a 4-day binge. Was smoking up bowl after bowl consecutively. Not normal for me. Guy that supplied us is reliable (relatively when it comes to this stuff anyway). He didn't admit that the stuff was weak or bad but brought another half (at no charge) of what we orig got from him. And that time the stuff was up to the usual standards. Since then we always test it first but havent had another problem like that.