What do I do. Need advise for first relationship.?

I met this guy about 2 months ago, since than we have exchanged emails, sms nd going out every weekend. He has introduced me to his friends, wants me to meet his family also some day. When he is with me he is 100% with me. Problem when he is not i feel he is out of reach. He seldom calls, very few sms. He told me that he wants to give 100% to his work when in office. But I am not comfortable with his prolonged silence. Is it normal or i am being panicky. This is my first relationship, so dnt kw how to go about it. Please help