Just remember you are in quit rehab. There are many phases to detoxing. As such, there are many emotions.
You can and must stay the course. Don't plan more than a day. Post roll, keep your word, and repeat if tomorrow comes. You quit daily.
Don't worry about how you feel. Just embrace it. You must be 100% determined not to have any nicotine in your system. That's all. That is the battle.
Soon, as your clean brain begins to rewire, things come into focus. You will love the freedom from nicotine. You will feel out of focus but it is only one of the phases.
It is hard but not impossible. I know from experience. It was so hard, I never want to cave and start day one over. That's why I loved the pain of it. The walk through hell is necessary but if you keep walking, you'll walk out of it.
I promise you that the dark rain clouds will part and you will feel warm sunshine on your entire soul. You will have that day when you look at the journey, take a big breath and feel healed and free!
Just Stay the course. Don't think in the long term of quitting. Think no more than 24 hours at a time.
Embrace the Suck and enjoy the battles. Write, Read, and stay close to the site. You will smile again, you will be truly living life vs. surviving as an addict.