well done for deciding to quit!
first day is fine, but it def gets harder. 3 days in and i was climbing the walls. you have the best motivation in the world though right now.
my quitting story is a bit weird cos a week in i got pneumonia and ended up in hospital. I was working at hammersmith hospital at the time though, so was exposed to all sorts of horrible bugs (it was a hospital one i caught), so don't let that put you off. however it made the cravings easier to get through i think cos i was so ill for a month! After i started to recover it came back though, i think the first 6 months are all pretty hard. I found it harder when i'd had a drink so at least there isn't that prob in pregnancy.
i had some patches and lozenges which took the edge off a bit. you can still have these when your pg.
make sure everyone around you knows and supports you through it. i gave everyone permission to give me a strong talking too if i looked like i was going off the rails. i also avoided anyone who seemed to want to make me stop quitting. throw everything to do with smoking out - lighters, matches, any tobacco products, ashtrays etc, it just makes it that much more difficult to do when your feeling desparate.
when you've done it though, its worth the feeling physically better bit and also the mental boost it gives you knowing you can beat it!