Why is he so unhappy?

My 12 weeks old has been crying since the say he was born. I really almost cannot take it anymore. It isn't really even the crying that bothers me, but rather the SCREAMING. The doctor told me it was colic, but I don't think it is. It is a matter of him always being mad and not getting what he wants exactly when he wants it. If I hold him, non stop, he usually doesn't do this, but holding him 24 hrs. a day isn't practical. He wakes up screaming every time he sleeps, and screams so badly while I try to make all of his bottles.He doesn't scream when anyone else watches him. I feel like I am at my wits end here and it is affecting the way I see my son. Is this just going to be his personality? Is this the way my baby is always going to be? Will I have to always deal with this? Every day is nothing but screaming and screaming and screaming and he NEVER stops on his own.