Is it an obsession? delusion? or am i just overly perceptive?

For the past 5 years, I've really really really liked this guy even though we've talked probably twice. I vaguely remember my first encounter with him but I really want to say I've always felt something towards him. This past year for some reason I've just kept thinking of him as my future husband. He is on my mind CONSTANTLY to the point where it's burdening. Whenever I see him at school I can't even look him in the eye and the nerves are beyond overwhelming. I'm not interested in other guys.

My grandpa has always said that the minute he saw his future wife he inevitably KNEW they were getting married. My question is can this type of (for lack of a better word) "sensory perception" be inherited? Is there a gene for that? Or am I obsessed? I never talk about it with friends because I feel like it's too much explaining and they would never understand. Please help?