Personal information

Oneday, in the Internet cafe, someone was talk to me. He is a short-term military person and work at National Health Insurance Corporation. He is a student at Hanyang University which is my brother in there too. He is 22years old in Korean age, that is same to me. We had a convertation and bacame friends. After a few days, his exgirlfriend called me and asked some questions. I felt bad and he apologize to me. After that situation, we knew each other phone numvers. He said to me "I can find your ID number". I think that is not big deal. If he really can find my personal information, I can't stop that and my information is not useful. That is my mistake. He find my ID number , several sites ID and secret numbers. He log-on my personal homepage, massenger, e-mail...etc. I felt terrible. I contact to his office and said how could do this. The office boss calls me and apolosize to me. Well, I'm not okay even now. I'm scared. Is he a crazy guy? I'm really worry about that he is really crazy guy.