Why do I sometimes get in these weird, bad moods?

It's like I'm a different person from how I normally am. Usually, in a normal mood, I'm quiet, but at least responsive, and just kind of feeling neutral. I'm also a caring person generally. But sometimes, I get this feeling like nobody really cares. Like something inside telling me that there's something wrong with me, but when I'm in this mood I rarely care about anything except my own feelings. I'm kind of stressed out from school and other personal issues (I'm 15, by the way), and it pisses me off that nobody seems to notice. Or maybe they don't care. Either way, sometimes when I feel that way, I get in that weird mood. It also sometimes makes me feel like I want to yell insults or burn something (I would never really hurt anyone though). So, what's wrong with me? Is this a normal thing for people that bottle things up?