There is nothing magical or special about January 1. If you made some resolutions and have already stopped them, you can always begin again today. God’s mercies and second chances are new each and every morning!
If you felt strongly about changing something on December 31st, it’s worth continuing your pursuit now even if you’re starting over.
Continue to work hard at that thing you really want to do. If you stop, start over again as soon as possible. Eventually the struggle will give way to developing a good, strong habit. And then, many will see, notice, and compliment you on the obvious changes in your life.
You’re not alone. God is with you to help you as you go.