Very hard Colette. I was really lucky as I got pregnant more or less just after I gave up. First of all, don't think too harshly of yourself for wanting to smoke still because you're still an individual with your own needs and problems, not just a pregnant woman.
Every time you manage to go without you should praise yourself, and every time you give in at least know that you tried.
Maybe take up yoga(with instructor trained to teach pregnant women)to learn other methods of stress management
I saw on a program once somebody suggested taking small sips of water through a straw every time the craving happened, I didn't do this, but took up chewing gum instead--orbit sweet mint, wriggleys extra, airwaves,...........totally obsessed myself with it, keep it in pockets, in my bag, all over the house,(still do) quite funny really!
maybe think about the things that seem to make you want to smoke: see if you can focus on them directly, and find other ways round them. Have no fear, if you really want to do this you will.
Repeat to yourself every day 'I am a good person'
followed by three positive things about you.
Don't worry too much, there are far worse things you could be doing. Just try try try, that's the best anyone can do in this life, and that's hard enough as it is!