Is it normal that i get annoyed whenever i think of him?

There’s this person who started giving me extra attention, making me feel all special but I didn’t pay attention to it. Then when I finally started thinking that he’s actually nice, He stopped reaching out. But he used to be on my mind since the beginning and I avoided him so he wouldn’t be on my mind. And now we have a lot of common friends so there is no way I can avoid seeing him but he also doesn’t talk to me like he talks with our other friends. It’s like he’s a completely different person when with me and another person when with everyone else. And now I just get mad and annoyed when he’s on my mind. I can’t even stop. Is it normal to think so much about someone you have nothing to do with and that it always ends up making me annoyed and angry at myself?