I'm not especially educated in these topics
but perhaps better informed than most.
The exercise item is particularly important.
In addition to the gym across the street,
consider regularly walking or running
or biking around your neighborhood.
Depending on how young your children are,
you might consider making this a family activity.
About healthy carbs . . . .
do you already like eating raw vegetables?
Cooked vegetables?
When you look at all your food choices,
consider making various raw vegetables your snack item of choice.
I usually keep one or more of carrots, celery,
cabbage, jicama, etc., on hand.
When I feel like munching on something,
one or another of those is my first choice.
About keeping a journal . . . .
it really doesn't matter what other people do.
What are you most comfortable with?
If it's typing onto the computer, do it there.
Not necessarily a blog for others, but just for yourself.
If you're comfortable writing by hand,
get yourself some BIG pads of paper . . . like legal pads.
If you enjoy dictating into a tape recorder
(or whatever the technology is these days), do that,
perhaps for transcribing later on.
I just remembered a book, "Writing Down the Bones",
which might be helpful.
also, one of Anne LaMott's early books, "Bird by Bird",
is good for inspiration in this area.
You probably need to make an appointment with yourself,
in which you agree that you will, with no exceptioins --
OK maybe an occasional day off -- consistently do
one or more of X, Y, Z every day.
Something specific and tangible.
Let us know how you're doing.