I had no symptoms this month, and got my BFP. Last month I had every symptom possible, inc hot flushes, what I thought was implantation bleeding, headaches, veiny boobs the lot!
This month at 10 dpo I had a very strange feeling in my ovaries and groin area, like a stretching pulling sensation which is still going on now, and now at 17 dpo my BB's are started to grow a little, but are not sore as yet! Thats been about it!
Its best not to think about it and push all possible pains to the back of your mind...I know its hard!
As for the smoking, apparently it can effect implantation - although I was a smoker (20-30 a day), but quit 2 days after getting BFP......afterall it does become a life or death situation, as smoking is known to cause miscarriage in some women!