Leo woman confused by Cancer man I'm crushing on..

Hello fellow Astrology fans. I love this site! I'm hoping that anyone who is knowledgeable about Cancer males can help me on this one.
For the last 2 months or so I have been slooooowly getting to know this Cancer man, we see each other when we are walking our dogs, he always stops and chats and seems pleased to see me. Just recently we seem to be getting closer, he's asked to join me on walks and we've talked non stop the whole way. I've picked up on his body language: he looks at my mouth a lot, tilts his head when I talk, smiles at nothing in particular, laughs at my silly jokes, approaches me when he sees me at the gym. It was all going so well and I know he's shy so I'm prepared to be patient (not easy for a Leo!)
On tuesday he asked me if I was going to an event at the weekend, I said oh no I can't but I really wanted to go, v sorry. Then the next day he saw me at the gym, walked past me a few times and completely ignored me! I walked up to him and he seemed to be in a hurry to get away. Plus he has stopped walking his dogs at the same time I do. I feel as though he is avoiding me now. Why had he gone into his shell? I feel really hurt and confused about this I would really appreciate your insight! Many thanks 🙂