Could be many things and hazarding a guess online with next to no data is risky and vague, at best, but those symptoms are classically bi-polar/manic depressive.
I have what is called Bipolar II disorder. It's a milder form of BD without the psychosis and other odd behaviors. You might be suffering from this. If this affects you life seriously, you should consider getting some help.<br />
It can't hurt.
If you are concerned, seek proper help. Speaking as someone with bipolar disorder myself, internet diagnoses etc can be very harmful & misleading. It could just be a normal hormonal change associated with puberty, or it may be something more, but nobody here can really give you the answers. Has anything you can think of precipitated this change?
If it helps, then vent away! We're listening. Also, a low sex drive is common with depression, but that doesn't mean that your teen hormones aren't having their wicked fun! If it helps to talk, then talk away. x
Maybe light bipolar , But I prefer the word mercurial.
Hormones are more powerful than most of us give credit. We're run buy them and teenagers are new to that.
You might be bipolar. Its when you change moods suddenly with no reason.
I have depression..so figured that's what it was...but read some stuff on borderline personality disorder...I don't know if you get angry a lot or not..but you might read up on it?