Stopping smoking is rarely easy. Congratulations on trying to stop. Smoking during pregnancy does increase the risk of premature labour, poor foetal growth, and later of cot death. You are in a difficult situation. You are likely to feel stressed trying to give up, and stressed if you don’t. In many people, the nicotine addiction is such that withdrawal symptoms are very troublesome, and agitation is a typical withdrawal effect. You don’t say how much you usually smoke, but it may be that stopping abruptly is unrealistic. It’s worth remembering that even smoking a couple fewer cigarettes a day is worthwhile. Having support while you try to reduce your smoking is usually helpful. Your doctor’s practice may well run a ‘smoke stop’ clinic and it would be a good idea to see your GP with a view to attending on a regular basis while you struggle with this issue. With all smokers there is a struggle between the part of them that wants to smoke and the part that wants to give up.
Unfortunately, none of the products that are available to aid giving up are suitable for use in pregnancy. You would benefit from strategies to help you relax, such as meditation or yoga, and it would be a good idea to join a class to start with. In addition, the NCT (National Childbirth Trust) run some excellent general antenatal classes to prepare you for labour and the postnatal period, which would be well worth attending.