WashiChiisai
Honestly, I don't know. My period did the opposite when I started on BC, went from 9-11 days eek to 5-7.
My guess is that it's just your body getting used to things. Since you're new on BC your body might be reacting oddly. It should be over shortly after starting on the new cycle of pills.
I'm not an expert, and if you are really concerned I'd say call your gynecologist and ask him/her about it. Periods and hormones do weird things sometimes, it's part of bodies figuring themselves out.
Good luck smile Well I'm off to a bad start, I skipped the pill today.
I'm just going to stop taking it probably... =/
Or I dunno. Maybe I should just keep taking it.