One of my classes which is usually awesome was having a very bad day. They took a long time to get settled, a few of them talk repeatedly during the lesson, and several of them were very obnoxious. This was my 10th grade class. I've started the biochemistry part of the course and I think it is too difficult for most of them. I've tried explaining it in multiple ways, practice sheets, ipad games, etc. I feel they're lashing out at me due to an underlying lack of understanding of the material. Overall, this has been a bad day. Any advice/suggestions?