Stopped having a period...

About 6 months ago, after the guy I was dating and I broke up, I stopped having periods until last Saturday, a couple days ago.  And it keeps going from barely spotting to leaking through a "Super" tampon in 45 mins. I have had awful cramps the past 2 days.  I'm curious as to why I stopped having periods in the first place. Has anyone else ever had their periods stop for multiple months in a row?