First, good job! I've been off the stuff for almost a year (July 1st). I can't tell you how much better I feel, both physically and mentally. The first few days are a bitch, and there will still be some bad days months afterwards. Here are a few things that helped me.
1. Stay away from smokers, when they are smoking. If your friends smoke, let them know you quit and ask them to support your choice. Tell them, firmly, to not offer you cigarettes or to smoke around you.
2. If you live somewhere that smoking is allowed in bars/restaurants.... stay away from those for a while until you have a strong grasp on yourself.
3. If you get a craving... do something. The longer you think about it, the more you'll want it. If I was alone when I got the craving... I shadowboxed. If I was at home... well, my fiance would always help me forget about smoking