If you've liked him all that time and not told him I guess your dreaming mind is experimenting with possible scenarios, much the same was as you probably have while you're awake. These types of dreams don't have to mean anything as such, just that you're thinking about this a lot and that the dream is a way of preparing for all eventualities - like the possibility that you may never talk to him about it, where he seems lost to you in a crowd. The dream could well be highlighting this possibility to let you know that he may get away if you never speak to him, or that it will get harder to speak to him the longer you leave it.

Athough it might not mean a lot in the most part, it could be possible that the other guy you mentioned does fancy you a bit and your subconscious mind has noticed this. It doesn't mean any of the things you dreamt are actually going to happen though.

The only real way to resolve dreams like this is to find out if he likes you the same way. Do you have any friends who know how you feel about him? Telling someone you know might make things a bit easier.