Painful Crush - Don't know what to do

Hi recently I gave a talk at a college on one of their courses and have developed an immense crush on the head lecturer there who invited me in. Since the day I visited there I can't get him out of my head. He's so perfect to me. Hes got lovely hair and smile. My parents work in the same department as him. At times I just think how much I want him. At the same time I feel as though I'm going mad and the crush hurts. I always find myself worrying whether somethings happened to him. He's invited me back again and I have ideas for what I could do when I go back. I'm worried he won't reply. Im also finding it hard to deal with the fact I may not see him or even if I did I may be disappointed for some reason. Moving on from this just seems too hard right now. I'd really like to hear any advice.