"High" can be used to a refer to a mental state, usually a euphoric one. This can be used to refer to an induced state of euphoria from drugs, but it is also used to describe other natural states of happiness (eg "I'm on a high").
"She's got you high and you don't even know yet"
It is impossible for anyone but the songwriter to say authoritatively what the song lyrics mean, but it seems to me that the song is about someone in relationship with a girl who is making them very happy. The girl may love the person, or they may even be in love but either the person doesn't realise it or is in denial.
"She's got you high" means that the unnamed girl has made the person euphorically happy, maybe that they are even in love; and "You don't even know yet" implies that the person has not yet realised they may be in love, or perhaps just what a good thing this relationship is.
Other lyrics from the song that support this interpretation:
You can't deny you're looking for the sunset
Perhaps this means metaphorically that the person is looking for something beautiful? Again there is a suggestion of being in denial.
It's the search for the time before it leaves without you
Suggesting that if the person doesn't realise this girl is a good thing and respond, she will move on.
What's this about? I figured love would shine through
The writer is saying that love should be obvious, but the person hasn't realised it.
Open your mind, believe it's going to come to
Telling the person in the song that they may be in denial that love will ever come their way, but that this is "closed minded" thinking.
You will find "It wasn't as though ..." is a relatively common idiomatic expression to mean
It wasn't true that ...
or
It never happened that ...
often contrary to expectation. Examples:
It was not as though he was the fastest runner, but over longer distances the horse could maintain his pace remarkably well, and often finished well ahead of the other horses in the race.
i.e. you would think the horse should be fast to win races, but this was not true.
"It was not as though I could move all these desks on my own," she thought to herself. "You'd think the headmaster would send some students to help out."
i.e. despite the headmaster's expectation that she could move the desks, this was not true.
Rowling's sentence basically means, "contrary to what you would expect from legal guardians, the Dursleys were not of any help to Harry when they were awake" -- a colorful way to say that they were of no help to Harry at any time, but they were least unhelpful when they were sleeping.
Best Answer
is being used in place of holler, just as
A common express is
meaning
usually (implicitly meaning) with some question
In your example, she is calling herself
in an informal, slangy sort of way.