It's not unusual to have a cycle and then have a longer amount of time before your next. Your body has to work hard against those hormones to ovulate, it's natures way of helping you not get pregnant while you still have a baby to care for. Less ovulation, less chance. My cycles were about 40 days long, but I have heard of 60+ days, or even women who have one period and then not again for some time.
Are you using some type of ABC or charting the cycle with NFP?