This is shyness on a scale that I can't really comprehend. I've written some (cringeworthy) letters back in my teenage years, but sooner or later was able to just come out and say something.
I think you need to ask yourself how long you're prepared to let this carry on for, and how much it could impact on your enjoyment of university life. It's so important to put yourself out there in the first few weeks, meet people and make new friends.
It's very easy to get caught up in the drama and fantasy of being really into someone, but that's not a real relationship. You've got to ask at some point, and he might say no, and it could feel pretty horrible. But we bounce back from these things, and no-one on this site can claim to have never had their affections rebuffed at some stage. Alternatively it might work out very well indeed, and you'll have something real to enjoy, but the key is action, and you can only do this yourself.