magic,
i think u should make an appoiment at your doctors firstly and get on some antideppressants , as you sound like you need them
also can u not look for other jobs jobcentre plus (in google) is good , if your work is stressing you out that much you should look for somehing else.
as you don't want to talk to family about your problems , can u not speak to a friend , mabye you should do some vouluntary work to get you out of yourself a bit , why are u ashamed??? its human nature to get fed up , u should really talk to someone are u male ? men never talk ! as for ur lack of friends u could advertise in the friends section of a local paper or join a local club
u must do something
draw up a plan and do it step by step mate xx