Congrats on your 5 days! I don't know your history, but I am a heavy nicotine addict as well, and I don't think quitting my drinking would have been as easy if I gave up my dip (snuff chewing tobacco), as well. It takes about 21 days to lose the physical effects of the nicotine addiction. I have quit that previously then ran into a stressful period of my life and reached for a cigarette, which led me to bumming cigs for a week before I gave in and bought a pack, but then I was smoking and coughing and I smelled like smoke, so I went back to dipping! Addiction is an evil cycle!!
Anyways, to get rid of the drinking urges I would stick close to this board, get out and get some exercise, walk, run, bike, lift, and maybe get to an AA meeting. The best way not to cave is going to be for you to stay active and to remember why you want to quit in the first place. If all else fails, I would give into to the nicotine and put off quitting that first and stay vigilant with quitting the drinking which is more mental. Hope that helps, and in reality we can all quit anything we want to. If you are strong enough to quit for 5 days, then you are strong enough to quit for 6!! Good luck!