Quit Now. Seriously. Now. When you look back, you won't regret quitting now. You may regret that for whatever reason, you lost the steam to quit tomorrow, and it's yet another 10 years until you try again.
Here is a link to your September Quit Group. That's where you will go early in the morning, every day, and post a promise to remain quit from all forms of nicotine for the rest of the day. Then, go there the next day and make the same promise, and repeat each day. We don't take weekends off, and we don't take holidays, birthdays, or sick days off. We post daily.
As for constipation, irritability, insomnia and brain fog, you know that's part of the deal. Part of the cost of years of stupidity. But, drinking lots of water, and exercise will help. Also, reading this site, especially the other intros as well as the HoF speeches. And, get to know the guys in your group. It's still early on in September, so you will be one of the early founders. Help out the new guys as they enter. Help them out, and lean on them when you need the help. Trade digits with some of them. Mine are just a PM away.