I found it SO tough. Much harder than I thought. I assumed the minute I'd seen the positive test that I'd simply quit and that would be it but it took me several weeks.
Things I did when quitting which helped;
When you get a craving think of the 3 D's; drink, delay, do something. So have a glass of water and empty the dishwasher for example to delay.
Then brush your teeth or eat some really strong mints - cigs taste foul mixed with mints
If do you cave and decide you're going to have a cig, cut the about half off of the top of the cig so as you're not having a full one
But before you light up, think of the following:
Think to yourself - would I do anything harmful to my baby when it's here? You'd never dream of smoking in the same room as your baby or letting it eat or drink anything harmful when he or she arrives, so why do it now??
If you keep it up you're going to be carrying a shitty, horrible feeling of guilt the whole way through and an even worse sense of worry that you have perhaps harmed your baby but you won't know until he or she arrives. And that wait will be painful.
Think of how the midwives will judge you when they deliver your damaged placenta.
You only have XX amount of weeks left - then you're free to smoke as much as you like!
If you decide to keep vaping, try out a few different flavours or brands. I used to smoke Marlboro and the guy in the vape shop was able to recommend a liquid with same strength that tastes just like Marlboro. I also upgraded to a good quality e cig. That really helped.
Good luck. It ain't easy.