Am I having a really bad sleeping pattern?

Yesterday, I slept at a regular time in weekdays in order to go to school tomorrow. On average, I sleep from six to seven hours, and I'm aged fifteen. And yeah, in the weekend I tend to sleep at three or four in the morning. I believe I need to fix that if that's the issue. However, in weekdays when I must go to school, I tend to not being able to sleep at all, making me go to sleep at midnight, sometimes even one in the morning. Recently today, I wasn't being able to hear my alarm clock, so due to that I got an extra hour of sleep by waking up at seven in the morning, when I usually wake up at six in the morning to go to school. Not only that, I've realized I start to doze off in my bus and sleep without even thinking I'm going to sleep. A few hours ago, I missed my bus stop without even noticing that I did, due to this sudden dozing off in the bus. This was the first time that happened, both of these events. Is it simply that I need more sleep, or is there something else that I have?