Congrats on taking off the nicotine leash, brother. Running free is uncomfortable at first, but trust me, you'll find it SWEET before too long.
First of all, nicotine does not keep you alert. What nicotine is doing for you, if you wish to look at it from that point of view, is reducing your WITHDRAWAL SYMPTOMS so that you can concentrate on what you are doing (until you need another fix, of course, then your addicted brain will demand attention again, and you will find it hard to concentrate on work....again). Think about that process, and understand that nicotine is NOT helping you. I hope I'm explaining this simply and clearly enough. If not, PM Wastepanel or Keddy for an explanation of the process, they have described it very clearly. Debunking myths such as "It mellows me out" and "it helps me concentrate" are key to you knowing that there is NOTHING in this drug that logically justifies it's use.
PM me if I can help. Congrats again on taking positive steps to change your life.