First of all, if you're a smoker and are wanting to get pregnant, you need to quit. For good. Immeditately. Before you get pregnant. Smoking during pregnancy can cause a lot of health problems for your baby. Exposure to second-hand smoke and smoke residues left on clothes can also cause health problems for children. If you want to bring a child into the world, you need to be responsible and do what's best.Now, as to whether or not you are pregnant, take a pregnancy test. That's the only way to know. But, since you were on depo for so long, there's a good chance you aren't pregnant yet. It can take up to a year, and sometimes longer, for a woman's cycle to get back to normal after being on depo. (For the record, the depo probably wasn't the cause of your weight gain. Studies have shown that hormonal birth control really doesn't cause weight gain.) It has long lasting effects, and as your hormones get back to their normal states you can experience a lot of different symptoms, many of which are experienced during pregnancy. So take a test, or see your doctor for a blood test.