regrets

I'm trying to deal with all the things that haunt me, that hold me back and keep me from being happy again.  And one thing that I've realized is that I'm very unhappy with how I've lived, or not lived, my life.  I love my family and would do anything for them.  But if given the chance to go back and relive or redo the past, would I?  I don't know.  Changing the past would almost certainly change my present which would include my family.  Would changing things then to potentially be happy now be worth it?  While I deal with issues now, would not having my family make me even more miserable? Or would not knowing what would have been keep me from the regrets?  And how many other lives would be different if I could change the past?  Several that I know of now.  But what other  people would be effected?   I almost wish that I could have the ghost of Christmas Past, Present and Future come to show me.  But what if what could have been is better than what is?  I can't imagine life without my family, but if I were happy in the "what-if" version of life, wouldn't that make my then family happy as well?  If things were different, would my mother have survived cancer without her "angel?"  

So the real question is not how could I change the past or what would change, but how do I stop regretting what I didn't do in order to make the most of now?