Thank you for your interest and questions. I believe in starting off with keeping things simple, and then with time broadening out to being more detailed where necessary.
I suggest that you keep a diary of your daily menstrual cycle.
Most women have either a 28 day cycle, or a 30 day cycle, and then some have a 31 day cycle. Then there are also women who only have one menstrual cycle every 3 months, or once every 6 months.
Start counting your cycle on the FIRST day of bleeding of your menstrual cycle. Should you have a 28 day cycle, then day 28 would be the first day again of your next menstrual bleed - don't become confused now! With a 28 day cycle, day 14 would be your most high risk day for ovulating. However, I always say the 3 days before ovulation, and then the 3 days after your day 14 are also high risk days. Just remember, that every woman is unique and different, and no-one knows you better than yourself. You need to understand your own body and the responses you have to what is happening in your life. For example, if you have a major upset, or are writing exams - you could trigger off an extra period in the space of a month. Should you not be eating correctly for example, with enough iron rich foods, you could either delay a period or even miss a period.
Having been on the pill for 2 months will give you sufficient contraceptive coverage. The pill (although you haven't indicated which one it is) should take about 4 weeks to settle into the systems of the body in order to prevent conception. It is absolutely crucial that you are 100% compliant in taking your pill at the same time every single day. Most contraceptive pills are listed to preferably be taken in the evening - should this not suite you, then you must stay with the same time every day. Certain medications like allopathic/pharmaceutical antibiotics and cough mixtures can cause the contraceptive pill to lose its efficasy, i.e. effectiveness. It is always advisable to commence taking the pill on the first day of your menstrual bleed - this will assist your menstrual cycle in being regulated correctly from the beginning. There would definitely have been a reason, once looked at closely, as to why your respective friends fell pregnant.
Having said all of the above, I always find it safest to advise and councel women commencing the pill, to give the pill 6 weeks to be fully effective, and at the same time to make use of a good barrier method like condoms, during this 6 week time span.
Should you be unsure, you are most welcome to telephone me, and I will talk you through any further queries. My direct clinic line is 021-4875435, between the hours of 09h00 - 16h00, Monday to Friday. Or alternatively, you can e-mail me again, always referring back to your original question, please.
All the best of luck, and enjoy your two week break!