Most Helpful Guy
He could be busy, or he could be scared off with all your relationship vibes. Most woman aren't displaying that they're only interested in a long term relationship so soon without allowing the guy to have some fun. That doesn't mean sex necessarily but I would personally be scared off if a woman showed such strong feelings so soon. He's probably keeping his distance so he doesn't hurt you later on, not looking for a serious thing right now.
He's single and wants fun, not worrying about commitments. The only way to get him interested again would be offering physical interactions, as it appears you were 'flirty' and I'm guessing that means you didn't let him get physical past just a kiss.
If you can't do that, I wouldn't wait.