I used the nicotine gum back when it first came out. You have to just bite into it a few times then put it under your bottom lip like chew. I had to quit drinking before I could try to stop smoking. Cigs and beer just seemed to go together for me. Keep the gum right where you would keep your cigs like your front shirt pocket. Then when you automatically reach for a cig the gum is there. The hardest time was when I first woke up in the morning because I always smoked a cig when I first woke up. So I would start out with a piece of gum and then a half hour later, when I had my first cup of coffee, I would slowly nibble on an oatmeal cookie.
Smoking is a oral habit so essentially I was trying to replace one habit with another. I would eat carrots, celery, nuts and crackers and such. Don't worry about gaining weight because it is normal to. Walk, run or bike; things that you really need your breath for.
Even with the gum and everything else I really had to put my mind to the commitment that this time I was going to quit. I know you stated that you have some psych problems, but I did and do too. Don't rationalize and look for excuses. Draw the line this time and say that by God this time I am going to ride it out and be free of this monkey.
I used the gum for about 6 months and slowly switched over to Trident. I couldn't go anywhere for a couple of year if I didn't have a pack of Trident in my shirt pocket, but I finally got that monkey off my back too :-)