Maybe make that trip to the store hard on yourself. Put your keys in one place. Put your wallet in another. Write a note that says I'm not going to the store and put it on your review mirror and another on your door. Make your house an obstacle course you have to pass through in order to go. Each obstacle is a physical reminder that you want to make a change today.

Reward yourself every time you make a good decision. A small sweet treat. A warm bath. Some cozy socks. Play a game online. Order yourself something nice. Buy a new book to read. Listen to a favorite song. Whatever.