He can't look me in the eye?

He can look at me with the big grin on his face when him and his friends come up to me. But as soon as I turn to him , he freezes and looks down. Looks back up and looks down. It's like he's scared of me. I'm not intimidating-looking. If anyone's intimidating , it's him. Taller than 6ft and broad shoulders. I'm only 5'6.

And yes. He can't hold eye contact when he's sitting down either.

I mean seriously , he can't hold eye contact with me for longer than a sec or two.

I know I'm not ugly (from what I've heard. not trying to be conceited) nor am I cross-eyed or have weird colored eyes. People have said I have pretty eyes so,

Why can't he just look me in the eye? I though people liked to look at pretty things? -.-

It sorta hurts me. Especially because when people say I'm pretty, I feel like their lying. This one time this other guy's like "hey sexy" and I'm like "eff off". I feel all weird just because this one guy can't look me in the eyes.

He stares at me a lot from when he thinks I don't know. But as soon as I make eye-contact, he looks at his shoes or he looks away.

What is going on with this boy?

And why is it affecting me so much?