It is not unusual in your life to occasionally get your period late or miss your period, especially if you are over 35 years old. Your ovaries are not perfect, and occasionally you may just not ovulate one month, and then your period may be delayed or skipped entirely. Most women have this experience some time in their life, and you are fortunate to have had such a perfect menstrual cycle up to now! I encourage you to wait and see. Your chance of pregnancy after a tubal ligation, regardless of method, is nearly impossible. When you do get your period again, expect it to be painful and heavy, as it will have had more time to build blood and tissue in your uterus than your usual cycle. If your period becomes irregular for more than 6 months, you may want to see a GYN doctor for an evaluation of your hormones and to rule out any medical cause. Once you get your period again however, the greatest chance is that it will go back to normal. I hope this advice was helpful to you and that I answered your question. Best regards, Dr. Brown