What is that queasy feeling I get in my stomach and the pain in my heart?

There's this guy in my high school and every time I see him my stomach feels queasy and there's this throbbing "pain" in my heart. But I tend to experience that when I'm not around him like on thee weekend or something like that. Does that mean I'm in like/ in love with him and I'm missing him. And that pain in the heart...is it "love"? O__O