The next few days are going to be tough, but you can fight through it. No one regrets quitting.
Some days are hour by hour. Seriously... I remember creating milestones throughout the day because quitting for an entire day seemed to long.
Have alternatives (gum, seeds, snack nuts, whatever...I once stuck a bag of tea in my cheek). Exercise helps a lot. Work out as much as you can. I found it to be the time when I felt about normal during the early days. I had workouts that were so good that I hit weights that I has not done in 15 years. If you need to, do some sort of body movement exercise every hour.
Feel free to jump in your group and contact anyone here for help or guidance or mere conversation.