That weird uncomfortable feeling

Ok so this guy says he really likes me, and I sometimes think I like him and other times I have this really bad feeling in my stomach and I am super uncomfortable. Like sometimes I’m super friendly and I love being around him and I want to still be the way we were now, and it seems like he’s willing to wait, but I don’t want to drag him along. I’ve known him since elementary school and we’re in HS now. I’m so confused and I’m wondering if anything good can come out of this...