The chances are low, but there is a slight possibility. As ksohkb stated, hormone levels can dictate the success of pregnancy after sex, however the 3-6 month wait before pregnancy, I wouldn't agree with at all. If you are really concerned, use contraception (condom, morning after pill) for 2 weeks until your new pill has had a successful handover.
Hope this helps,
Adam
You need to be off the contaception pills for 3-6 months berfor you can get pergant, but this is only the average person it could happen sooner or later for you depending on your hormone levels.