Seriously, why am I so shy?

Well you could try writing him a letter for you to express your feelings a little more easy and after that it will be easier to express yourself in person, I don't think he got pissed off like the answerer above believes, I would have been confused and sad if a girl rejected such an offer from me, so what I recommend is that you give him a call and explain to him what really happened, tell him that you wanted him to hold your hand but its just that sometimes you get a little shy (which sounds fine if you are a girl) or it doesnt have to be necesarilly shy, you could say that you were confused or that you were just expecting him to grab your hand and not ask and got caught off guard, the reason I am telling you is because I think about it and if I were in his shoes I would love for you to call me back and tell me that you didnt just mean to reject me, the truth will sound way better than what he actually might be thinking right now, he might be thinking that you already have a boyfriend, that you dont like him, that maybe he got his hopes up too high etc... just be honest, and if he really is a gentleman and the one for you he will understand and wont get mad or upset about it, and if he does (which I highly doubt) then that only means that he is not an understanding person and people like that you should avoid. Hope this helps friend :)