Do i have to take a oral contraceptive if me and my bf have only time to make love once a month?

i have a bf working far from me and we meet only once a month bec. of his schedule and mine too.on wed we suppose to meet and i will take nordette (oral cotraceptive) on tuesday because that is my 5th day of period and on wed he will meet me and thursday morning leave again to work for our coming wedding.I am a first time user of this contraceptive and i am planning to staop it as soon as he left and take again when he will come back to see me.my question is,if that is my way of taking a pill do you think it could lessen the chance of preventing me from pregnancy?I don't want to take it everyday cause it's not everyday that i make love to my bf.I don't have time to see a doctor to discuss this but i hope somebody there could help me or give me an idea.thanks a lot...