Hi, I used to smoke but quit a few years before getting pregnant. My recommendation would be not to think about the three month mark - I know so many people who said 'I'll quit after I've had my surgery' or 'I'll quit after I will have lost the weight' and it just doesn't happen. You will find another milestone to count on so you have to quit now. THe only tip I can give you is to take it one hour at a time. When you get up, don't have your usual routine, think of something new to do - go for a walk instead of having a cup of tea, or have a nice smoothy instead of a coffee. Than you'll realise one hour has passed and you haven't smoked.
Don't hang around people who smoke, just let your friends know and ask them not to smoke around you. Don't go to pubs, try new things. Then you'll realise it will be lunchtime before you know it, you will have smoked 0 cigarettes and you will be so happy with yourself.
Once you get through the first three days, than you can take it one day at a time, and every night you will be so happy with your achievement. Then it will go to one week at a time and before you know it you will have a beautiful baby.
I'm not trying to lecture you (because I know it doesn't work) but this is not just because it increases risks to your baby, but has a huge impact on your health. You will be a parent, and your child will depend on you, and you really really don't want to get ill (I mean, seriously ill). I know you probably think 'this won't happen to me' but cigarette kills people every day, in this country and all over the world. HUNDREDS of people. So quit now, for YOU and for your baby.
SPeak to midwife/health consultant. There are hundreds of resources to help you quit, really good support out there including constant contact, text messaging, counselling, etc...
If you feel like smoking, just log on and someone here will be there to help you.
Take care,
BP