Find something to do with your hands like writing a letter to your baby, drawing, cleaning, or cooking a healthy snack.
Carrots helped me lol it was my healthy pretend cigarette lol. I would chew on one when I had a craving. I also let people know that I would be ill or grumpy because I quit. After a week or 2 those side effects go away. The only thing I catch myself doing is thinking about smoking and it's been months. I ask myself why would I want that I feel better now that I've stopped my breathing has improved and by baby is going to be healthier without them.
I quit with my last pregnancy and stayed quit until he was a year old. For some dumb reason I picked them back up. Thank God I got pregnant again because it made it easier to quit again. This time I will not pick them back up. Plus my husband quit with me this time yay!
Good luck you can do it and just keep reminding yourself it's better for your health and the baby's.
Get hard candy and when frustrated pop one in your mouth and think about your future baby, all the good stuff. Thats what i did when i quit smoking and it helped. I also saved a picture of the health benefits and looked at it whenever i wad doubtful. It feels so good not to be attached to something anymore =) best of luck, you can do it!