The summer before I registered for my final year of college, I had an all-summer babysitting job for three little boys. The twins were awful. They were nuclear disasters waiting to happen, and it was a constant fight to keep them under some kind of control.
I started bleeding all the time. It was constant. I'd finish my period, have three or four days of not bleeding, then I'd start again. I saw an OB/GYN and he basically told me it was stress, and when I finished the job, my periods would probably regulate themselves. He did put me on the pill for the last month, and it was great. It stopped the bleeding and regulated my hormones so I didn't feel so frazzled out all the time.
My periods weren't just early, but were also constant that summer.