Starbrite, I'm so sorry you're going through all of this and are having to deal with the emotions involved in it. I agree that smoking does seem to affect one's metabolism. When I quit smoking, I gained 50 pounds seemingly overnight. I realized later -- for me -- it was because I was using food to replace the oral fixation of not having a cigarette to puff on. Not saying this is what you're doing, just relating my experience.
I agree that you might need to adjust your calories downward. I just googled smoking cessation and metabolism and there are several articles that indicate that smoking increases your metabolic rate mainly because it speed up your heart rate (thus leading to heart disease). It said in one article that smoking 20 cigarettes a day is the equivalent damage to your heart of weighing 90 pounds more! WOW.
So, congratulate yourself on stopping smoking. And make some adjustments on your caloric intake and keep up the exercise and you'll win this battle. You have done so well with your weight loss. Don't let this set back take that away from you.