me and my boyfriend had sex on 27th Feb 11 and my regular menstrual cycle should have started on 8th March 11 but till now (16th Mar 11) i havent got it yet. Am afraid tat it would lead to pregnancy . My last menstrual cycle was on 6th Feb 11 . Please suggest some natural ways to avoid me getting pregnant .. can it be done naturally or should take any pill ? if pills please suggest what pills should i take and it what time interval . Please reply urgently .