hookup get bored of me

We hookup for 2 times. After that he seemed like getting bored of me. He didn't text me or reply my text. So I sent him a message "I'm thinking maybe you are getting bored of me. But it is okay as I had lots of fun with you. I've never done that before. I consider it's good life experience. But maybe, I would not do it again." Then, he replied back " you're so sweet." I wonder what he means. Can someone tell me what he means for saying "you're so sweet" ? Thank you!