i found all sorts of silly things happening after i was on a bc for a year or more. ive been on ortho tricyclene lo for over a year now though and i plan to stick with it. my periods are almost never the same. but typically really start around tuesday (sometimes i start to spot a week before my pd! sometimes i dont spot.) sometimes it lasts 4 days, sometimes 6.
i would think that you are probably just fine.

also, i have that shirt in your icon!