I go through stages when I can be happy without a care in the world, I feel as if nothing can bring me down.
Then there are other stages when I just don't feel like getting out of bed.
I completed high school last year and throughout the whole year my emotions were up and down and I felt like there was no-one I could speak to about this. At times I would just sit in my room and cry myself to sleep. My parents never really thought much of me spending so much time in my room, but that because I'm a bit of a introvert. My social life dwindled into almost nothing. I would make plans to go out with friends but would cancel on the day. I would go to a friend to sleep over and later into the night I would be so upset because all I wanted to do was go home and sleep. So eventually I stopped sleeping out for a couple of months. I sleep out nowadays but not as much as I used to. This year I'm having a gap year as I'm not sure what I want to study yet, so i've just been at home. The whole day i'll sit by myself and then when my parents get home I'll just go sit in my room. Little things they do annoy me and I'll get irritated easily sometimes.
I'll feel tired at night but won't be able to fall asleep until the early hours of the morning and I'm an extremely light sleeper so if I get waken up I struggle to get back to sleep. (For instance I wake up when the cat or dog walks into my room.) Other times I'll feel so tired that I'll go to bed around 7:30 and then wake up feeling tired and just don't feel like getting out of the bed. My eating habits have changed as well before I had a more healthy diet recently I've lost my appetite. I also jog every second day, now whenever I think of jogging it just seems like so much effort and if I do go for a jog afterwards I just go and lie in my bed. I also have anger issues which come and go and can sometimes result in me punching things, throwing things around and just being down right rude. After these episodes I'll feel extreme guilt and just feel sorry for myself.
Please help me make sense of all of this please.
You certainly do present some classic depressive symptoms. But the highs you describe (and the anger) combined with the lows, well that could be something else. I think you should consider going to a doctor; if you do have some type of disorder, it's not only not going to get better on its own, it's very likely it will get worse.