I work in an office with more than a hundred employees and I have a small circle of friends I usually have lunch with. We've been work friends for 5 years. We don't meet after work so it's not a close friendship.
In September, one of them started to talk to me more. Due to the new hybrid mode at work after Covid, we split the office days and my days matched his so there were many times when we had lunch alone. He's five years younger than me and single, I am married and have a kid so we don't have much in common but we get along and he seems to enjoy talking to me because after Christmas his attitude started to change. He started sending me messages after working hours (when he traveled, when he bought something he wanted to show me, etc...). He also tries to have lunch alone with me and if someone else joins he's clearly upset, so some people have stopped eating with us and leave us alone. I noticed he remembers each and every detail of our conversations, he sends me links to Youtube songs because they reminded him of me, and in an after work mandatory party he didn't leave my side until 3 am, which felt pretty weird to me and started a lot of office gossip.
To summarise, he only talks to me now, he got distant from the group, if I'm not in the office he prefers to eat alone and he seems to be everywhere I go in the office. The issue is, I'm very professional at work and I don't want anything to damage my place in the company. I don't like all this attention but on the other hand I wonder, am I overreacting? I mean, what does this all mean and why me? There are plenty of young, single women in our office so why choose me to spend time with? I'm not very attractive and I don't have one of those charming personalities so I'm really confused. Should I put more distance between us after 5 years?