teaching my first lecture/course

I have just finished the 6 lectures I had to teach as a university teacher, not an assistant. As assistant I am well experienced, this was the first time I was allowed to pick my own subjects and teach them. And test them. Problem was that there was no book with the course. on which I have had no influence. So the students had to learn the slides and one article that came with each lecture. Of which I reminded them. But hardly anybody took notes. I even saw students doing homework for another course. Welllll, the grades were as to be expected: 18 of 30 students had lower than 55% correct. Only those people who made notes and responded to the interactive bits scored higher. I am so frustrated. I made the questions while preparing the slides, so I KNOW I covered the topics I had questions on. Plus most of the questions were about something we covered interactively in class. And the first question was an exact copy of the person I adopted the course from. The first sub-question was about stuff they did in first grade, and something we repeated 4 out of 6 tests. Hardly anybody new the answer. Wondering what the coordinator will say about this massacre. I strongly feel this is Not My Fault, since there were students who got 100% correct on sub questions, so they were not that hard...