Summertime Sadness

I think this is her reliving some sort of fast-paced, almost destructive relationship with a guy. You know, one of those "I'm deeply, dramatically in love with you, I'll die without you" kind of things that almost every girl has at one point. And now, she's looking back with melancholy nostalgia, because it was passionate and dramatic and beautiful, but also not meant to last. The whole summertime sadness is the beauty of this ephemeral relationship that ended too fast, and can never be recovered.

"Oh, my God, I feel it in the air Telephone wires above all sizzlin' like your stare Honey I'm on fire I feel it everywhere Nothing scares me anymore"

Here she's remembering it, and feels like she's so much more wise and experienced from this.