Weird cycle, help??

My cycle generally lasts about six days, I cramp real bad on the first, and it’s usually pretty heavy. I’ve never had spotting before, and I’m 17. The last cycle I had lasted twelve days, no cramps, and extremely light bleeding. My next cycle isn’t supposed to start for another two weeks, but I just went to the bathroom and I’m bleeding, but no cramps. This is really really weird for me and I don’t know what’s going on. Has anyone else experienced something like this??