WTH Just Happened?

Pre-Board

I stand at the start of the passage, just beside the teachers' cabins, Jasmeet next to me, still holding me by my arm. I think I'm gonna need that support for after what I see, I somehow feel myself lose my sense of balance.
Right in front of me passes Mr.Y, heading from the left -the area with the Physics and Biology Lab- to the right. By face, this is the guy I saw earlier, but I'm perplexed as I fathom that he is taller, and even broader, probably because the last time I saw him, he was leaning against the wall, which made him look a bit shorter. His hair, longer than before, covering most of his forehead now. But I like them that way. "Whoa", I say under my breath. With a charming smile on his face, he strides across the corridor in all his glory, his eyes focussed on a girl-the same girl he was talking to the other day-who is asking him something. She has her bagpack slung across her shoulder and he's carrying some papers in one of his hands.
Jasmeet drags me to the girls' washroom (actually the female staff's washroom which the girls of my school like to use sneakily, more than the one they are bound to) on the right, which makes us walk right in the middle of the two of them. But considering the distance between them- about five metres or so- we aren't noticed.
"How did it go? How many questions did u leave?", the girl asks Y.
"I left a lot of them.", he aswers just as we pass by him, still smiling. I safely presume they are talking about their pre-board exam they had today.

"Just wait here outside till I get back.", Jasmeet tells me as we reach the washroom door.
"But I....hey don't leave me here alone!", I say, but too late, she's already gone inside. I call out to her a few times-no reply. I decide to focus on what demands my attention at the very moment.
Y and the girl are still talking, another girl joins them. I crouch down a little, pretending to tie my laces, as I glance at Y from under the railing. I can barely hear them, or maybe I can but what I'm seeing is overpowering my hearing ability.
I don't wanna take my eyes off the guy. I have to admit, I'm bowled over. The moment he walked right across me, I know I felt my eyes widening as they do when I see someone really attractive. Besides, he is tall, really TALL. And tall men are my weekness, especially when they have such an alluring smile.
I'm giggling like an idiot, for reasons beyond my comprehension, when Jasmeet finally gets out. "Let's go", she says. "Wait, no! Just a few more minutes please.", I request her. "Samaira, it's English period, and we're already five minutes late. You wanted to see him, right? You did, so let's go now."
I'm still trying to convince her to stay a little longer that I turn around only to find Y and his friends no longer there. "See! We lost him. He's gone! All because of your stupid argument, you idiot!", I almost yell at her. She just changes her expressions in disgust and moves towards the class.
•••
Ms. Neha's given us a class assignment to complete in silence. I feel thankful as it gives me some time to reflect upon the happenings that took place in the previous period, in peace. What happened to me, the moment his tall figure walked in front of me? I almost lost control of my senses. Why was I giggling, and what happened to me when I saw him no longer there. I think my head's gonna explode.

"I so wanna see him, too!", an excited Naina says from behind.
"I wanna see him again, too", I say. "I've gotta have another view."

Suddenly I wanna know everything about him.

What did just happen with me?