Ay, ito talaga ang mahalaga, please talk to your doctor or nurse about this, ha! Bawat tao different ang timing at effectiveness, at sila lang ang makakasabi ng tama para sa iyo based sa schedule mo. One of my mum friends got worried din about the same thing, kaya she called the clinic and doon siya nakakuha ng peace of mind. Better safe than sorry talaga when it comes sa family planning, no? Good luck, sis!