Uggh why do guys do this, especially this guy.

A new guy in my life seemed super interested in me. I didn't get the vibe from him of sucking up to take advantage of me. He went on and on about me. Said he felt like he was falling for me. He doesn't have it all together in his life, but neither do I. He seemed somewhat insecure about his life. I think he's at the age where you're transitioning from party days, to more family time. He seemed to enjoy talking to me and really appreciated some feedback I gave him. But he hasn't talked to me for a few days. Won't respond to any of my texts. It's so weird because I felt a mutual likeness towards each other.