Search Results: interpreting his words

Hello. Here is a short summary of the story.
I have been attending to German classes. Our teacher is a young guy, he is quite smart, but not particularly handsome. I noticed that he stares at me sometimes, but of course I did not interpret anything from this. And once at the lecture, we were reading a text and the question was ''What people lack in their lives?'' One of students answered money. And he said ''love'' and looked at me, I just smiled and immediately looked in my book.

After a week, I saw him in church, in the end when he left he saw me and smiled.
Then during one of the lectures we were learning the vocabulary. And there was the word - flirt. He asked me do you think that people flirt at the church? I smiled and said no.
Then for the second time, there was a topic about a couple flirting, he looked at me and smiled.

But after the lectures we say goodbye and never talk to each other.

I decided to add him on Facebook, thought maybe he is just shy to talk face to face. But he did not write or like anything. Then I wrote him ''Thanks for accepting''. His answer: ''You are welcome.'' And nothing else.

I was quite grumpy during the next lecture, maybe even a bit angry.
But I thought that it was silly and today I was smiling, but this time he seemed grumpy. Then we I began to look at him, he also look at my eyes and smiled.
Anyone out there can help me to understand what is on his mind? Because it becomes annoying. What should I do in your opinion? He is 3 years older than me.
Thank you