Conceiving once finishing contraceptive pill

Patient: Hi I just want to ask if there is a chance of me being pregnant. Ive been taking the contraceptive pill for years now (mycrogynon 30) but last month the mucked up on my prescription so i have been off it this month as it didnt arrive on time (i actually still havnt got it) the other night i was with my boyfriend and i totally forgot as im so used to always being on my pill i stopped things nearly straight away but there was still penetration at for a couple seconds he didnt finish we stopped completely then . I understand that it is very difficult to get pregnant straight after coming off the pill also there is a slimmer chance because nothing actually went ahead … im also a smoker so im sure this doesnt help