you are supposed to start your pack on the sunday after your period starts. you can start monday and be fine, but your period might be thrown off a day or two. if you want to correct not starting, then take both pills on monday. one in the morning and the other that evening and then stick with the one a day. you are protected all the same, but do understand that with only 2 months into the pills you still have another month or so before it is fully into your system. but i sometimes forget to pick up my pills to start sunday, so i just double up the first day and have no issues.