Why is my dog so afraid of me?

Its just really recently he has been my dog for 7 or 8 years now and I have never been abuse to him I give him treats and pet him and stuff but really recently whenever I walk In the door he barks at me like he has no clue who I am and when I go to pet him he runs scared and he is the only one that does i have another dog that is only a year younger and he isn't scared and I have another puppy who is s great Dane Thad not scared but this yellow lab is so frightened of me and I don't know why he has been my pet for so long