chris
I'm not a professional but you sound depressed to me and need something more than family in your life to bring the joy back.
Is it absolutely necessary for you to work 50 hours a week?
Is it possible to change your job to something that you look forward to going to every day.
Life can be short try and put something into your life outside the family situation which you are happy about.
Keeping a journal is a good way to get your feelings out, keep it private so the family don't read it.
Do you have friends you can talk to about your situation?
Try if you can talk to your husband about how important it is for you to get away for a few days at Christmas.
Life can be hard I know I lived in poverty all through my childhood and into my early twenties but we can get through the hard times.
Downloading old 2960s films etc
I was not well enough to be bothered in fact quite apart from feeling that I have done all that thanks, got the t-shirt etc and don't need it anyway. We are all different and thankfully in our case we rarely have much contact with the 'other' GPs nowadays and funnily enough, in spite of not changing their nappies, we have very good relationships with all the GCs. As my DH says they don't remember having their nappy changed never mind remembering who did it! The world will not stop spinning if you back away from all your caring roles until you feel you know what you want to do in the future so I would recommend that is what you do and change direction completely. Perhaps you need to write out your own 'bucket list' and then go for it! Look after yourself because it seems you are very much taken for granted. 
