Shyness has ruined my life, is there a way out?

I am 30 years old and my social phobia and anxiety has meant I have been unpopular and unloved (except for blood family) throughout my life and it has lead me to have a very limited and lonely life with few close friends most of whom are moving on with marriages and kids etc. I thought I would "grow out of it" but it hasn't happened and don't think it will just go away as I am 30 now. I avoid most social situations because of the intense internal pain they cause me and haven't formed a proper friendship since I left school. I have been in relationships but they have failed, probably due to my insecurities. Is there a way out of this living nightmare?