Kurt overdramatized things by nature, and he knew it. Part of his diva nature, this tendency for hyperbole made him persuasive. It had helped him get out of many a spot and also, of course, given him the best Lady Gaga costume. So when he told Mr. Schue that he was in love with Blaine, he was intending the comment to be an exaggeration. It wasn't until he had blurted it out that he realized just to what extent it was true.
Sure, Kurt wanted a boyfriend. Someone to fawn over, someone who would fawn over him in return. And although he told people he was looking for love, he hadn't really been. He was looking for someone to hold him, to recognize who he was, that was all. And someone to share his first chosen kiss that counted.
Blaine fit all these. He was the first boy to pay attention to Kurt, to care what Kurt thought (not about music, but just about life). Kurt wanted Blaine to hold him, give him an indication that perhaps they could be more than friends, but Blaine so far had remained distant. A friend and mentor, for sure, but did Blaine feel that Kurt could be boyfriend material?
So that's what Kurt meant to tell Mr. Schue when he came for advice on Sue's Secret Santa gift. And he did, and that's probably what Mr. Schue had taken away from the conversation, but Kurt told himself something more. His attraction to Blaine wasn't a simple boyhood crush. He loved everything about the boy – his hair, his dapper manner, his voice (Blaine had the voice of an angel), the way Blaine seemed to understand him and encourage him in everything, and not to make him feel stupid when he messed up. Blaine was the only boy, no really, the only person that made Kurt feel whole. So he realized he wasn't exaggerating when he said he was in love with Blaine, he really had fallen for him.
Kurt wanted to tell someone exactly how he felt, and he was pretty sure it couldn't be Blaine. He took out his cell phone and dialed Mercedes.
Disclaimer: I do not own Glee or the characters from the show.