Should I keep my hopes up?

My friend told this guy that I liked him (with my permission) and he said, "Oh, cool." He was ignoring me for about 5 days until my friend came and told me that he didn't just say "Oh, cool." he said that he didn't like me. I was a bit pissed that no one told me. On Friday my other friend told me that she talked to him on Facebook and that he said he was starting to like me now. It made me really happy, but should I keep my hopes up? He said that he was gonna wait a week and see if he liked me a lot. What are the chances that it was just a spur of the moment thing that wont last?