Most smokers I have known, did not quit while they were under stress, because it makes more.
Exercise is a good thing. As you get in better shape, you'll probably find you want to give up the cigs. But you won't be able to give them up until you decide you REALLY want to.
I have really, really enjoyed bellydancing - it's a good workout, and it's just a lot of fun. I realize a lot of people snicker at this - go ahead - and others say things like "oh, I could never do that because I'm too fat/uncoordinated/undisciplined/insert your choice of excuse here." But it isn't about that at all. In my class, there are women of all shapes and sizes. All you have to have is a sense of fun.
Find something YOU like to do. Do it. You'll be amazed how it changes your attitude.