When I was still on the quitting/failing/quitting/failing merry go round, I didn’t realize that smoking made me feel worse, not better. Stepping off that cycle is hard, but you’ll be so proud of yourself when you do - and you will cherish your freedom.
I like your note that you will need to do something different this coming Sunday. Make a plan and stick to it. Be especially vigilant any time you are HALTed… Hungry, Angry, Lonely or Tired. We (ab)used nicotine to take the edge off those feelings, and they can be big triggers. Quitting is a time of experimenting with new responses, not relying on smoking to pickle our feelings.
Try again - you CAN do this!