So, up until last year, my period were totally normal, with very little deviation. I bled for 5 days and had typical period symptoms, every time. 

Last year, in March, I had a weird experience where one month I had a really long period. I felt the usual PMS symptoms and a few days later, my period started. I put on a pad and went to bad. Woke up the next morning with next to no blood. For the next several days, I barely bled at all, didn't even bother wearing a pad or a tampon. I was barely spotting. Then days went by with no blood. Then I got a bunch of blood, like a normal period for several days and then it was over. I experienced no period symptoms during the time that I was actually bleeding. It didn't 'feel' like I was on my period. There was just blood coming out. All total, this lasted about a month. Then the next month, I got my period as normal (5 days of bleeding, normal symptoms like cramps and lower back pain, felt like I was "on my period"). And then for the next several months for the rest of the year, my period was normal. Then this month, it has happened again! I got another weird, long period.

So, does anyone else experience this? My period is absolutely normal 11/12 months a year, but I have 1 month with an extremely long and strange period. Does anyone know what can be causing this?