Is it normal to have always had drastic mood swings?

It's actually been like this ever since I can remember. I might even have some sort of personality/mood disorder, though I have no idea which. As a little kid friends would come over and ask if I wanted to play and some days I would be all for it, bouncing on my heels in excitement. Other days I slammed the door in their faces. It goes deeper than that too, sometimes being shy and stoic faced, the next day bubbly and energetic. That's still something I struggle with except NOW there's more sides than ever. One that's bubbly & ditzy, serious & sarcastic, joking & easygoing, intellectual & philosophical, one that wants to go out and travel, one that wants to stay inside and read, one that wants to make everyone in my life happy and have fun, and finally one that wants to destroy everything around me and then act like nothing happened. My little brother asks me whether I'm "mean ____" or "happy ____" today omitting my name, obviously. I either pick him up and spin him around or push him aside and am extremely rude. The scariest part is this doesn't change day by day or week by week. It doesn't have any sort of schedule or predictability, it just occurs when it does and I'm surprised people who've known me as long as three years or more stick around knowing it. I don't notice it because it's something that's always been a part of me but recently it's been brought to my attention and it hurts knowing that the people I love have to cope with this sort of thing. That means when I lash out at them or am unexpectedly rude or irritable, I might come back five minutes later joyfully talking about something else or not talk to them for a while, though even then it's still a shorter time span than the average person holding a grudge. It makes me unable to ever fully agree or disagree, think one way or another on a certain opinion or idea. It's not entirely bad it helps with open mindedness but I have no idea how people can be certain on one opinion when I'm hard pressed to choose from so many thoughts floating around my head. Mainly applying to my personality and mind, it's also to an extent external too. I change clothes quite a few times a day simply because what I'm wearing no longer suits my mood or personality. Thank you, I'm done rambling. <3