Carol,
Sometimes it is good to look back to review the life lessons it has given you. Other times it is best to try and forget the past (once you've learned those lessons) and just move on - especially when the past hurts.
I've found that keeping a journal helps a bit. Not a fancy bound journal that needs to be written in every day. Just a notebook that I use to jot down thoughts. Sometimes these thoughts are what are bothering me that day. Sometimes it is good things happening. Sometimes it is when I'm most down and I make myself spell out the blessings I do have. I feels good to get the emotions down on paper. Often I will go back and read them, espeically when something similar is going on weeks later. I've been doing this since last year and it has really helped me. Looking back at some of those early notations they seem so trivial now, but they were important at the time. I use a two part notebook and keep a positive attitude by using the front section for trip planning - one of my many blessings is that we do some great vacations and I get great joy in planning them. Perhaps you could use a section for your dreams for the future.
Maybe something like this will help you.