Is this normal that i am seeing this? am i going crazy?

Okay yesterday I went to a restaurant with my family and I swear I saw a member of a group I like Yesung I looked at him for like a good minute then I looked back like literally a second later and he was gone then I heard another members name in someones conversation after that while I was eating I saw there van that the group is always in when they are traviling going to there concerts and everything I know it's there cause I always see them come out of it in videos but it can always be someone else