So confused.. Never had this happen.

I'm super confused.. My period has been regular since the first time I got one.. One period every month. Including 28 cycle days. But for some odd reason I had 2 periods in March. The second period I had in March ended on April 1st. So I thought that basically was my April period. (That's where I got confused. It's never happened.) But then later I had a period in April.?? Now it's May & I should have started the 23rd but af still hasn't made an appearance. Getting very frustrated because I don't know why this happened. Does anyone have answers.? I'll post pics of my calendar.