Should I be concerned about this guy's behavior with me at my school?

Yesterday when I walked in the school to go to class there was this guy (student, a little younger or about my age) standing in the hallway looking at me for a minute or two like he was staring (watching). I caught him doing this at the corner of my eye. But when I looked at him he looked at me for a few more seconds and then started walking down the hallway into the computer room. When I noticed my teacher and classmates wasn’t in the room, I looked the other way and saw my teacher going into the computer room. So I went down there and when I walked in, the guy looked at me again for a second or two. Then when I was standing outside waiting for my mother to pick me up and when I saw her coming, I noticed the guy at the end of the building by the corner looking at me again. But it made me feel like I was being watched or something. It gave me the creeps. Should I be concerned about him? He looked like didn’t smile and just had a blank/normal look on his face. It made me feel like I was being watched. I didn’t know him either.