Is it normal to have two periods in a month and none the next? not sexually active

It can be, sometimes: A woman with cycles shorter than 29 days (shorter than a 30-day or 31-day calendar month) will likely have 1 ovulation per month during 11 months of the year, but have 2 ovulations during one month of the year (since she has about 13 cycles a year). If she is irregular, such as a 26-day cycle followed by a 36-day cycle, she can have 2 periods the first month and none the next month.