Search Results: signs he is interested signals

Do they mean someone's interested and too shy to express it or that they're just not interested?

The exact situation is this: I met this guy while going out with a group of friends. I thought he was cute and we got along well and he mostly talked to me, walked with me almost constantly although we didn't know each other at all beforehand. Whenever I said I was against something or I didn't like something, he'd side with me. For example, I freaked out when I saw a moth and while everyone started making fun of me for being such a girl, he said that he usually ends up being the moth killer in the group and that he's pretty good and if I didn't want to go into a certain place, he would sway the group to go somewhere else. However, throughout the night, he'd get randomly quiet and then go back to being talkative. He also hasn't added me on Facebook so far. :/ Sounds petty but I thought that would be a sign of disinterest right? I don't think I showed interest because I was too shy since we were in a group of people and I didn't want to be obvious about it but then again, he didn't either really - he didn't flirt with me or awkwardly ask me if I'm seeing anyone. I usually can pick up signals really well but with this one, I am so confused.