Help im being stalked what do i do?

Im being stalked by my dad..he is really controling and a few years back i decided not to live with him now im 18 and he found out my address and keeps sending me letters to see me...he came up to the house when i wasent there and was banging on the door asking where i was.My mom called the cops and they personally called him with a warrent of arrest.So he had a family friend come to me uninvited asking me things..i diddent give a straight answer on anything but still im really scared