Hi Bridgey - I came off the pill in July 2010 and I had about 8-9 months where I spotted way before my actual period. My husband and I weren't TTC then, so I never had the issue of wondering if it was implantation bleeding...I knew for sure it was just a messed up cycle. I had all my hormone levels checked as well and everything came back normal.
Now, about 14 months off the pill, I still spot for 2-3 days nearly every cycle and then my normal flow is sometimes as little as 2-3 days....so I very often spot for just as long as I have a normal period. My doctor has told me it's no big deal and everyone is different. As a side note, pre-pill I had 28 day clockwork cycles...now I range anywhere from 30-35. I believe whole heartedly that the pill has had either a longterm or permanent effect on my cycle.
I'm guessing it's just still your body re-regulating your hormones and "learning" to ovulate again after being suppressed on the pill. Hope helps relieve some anxiety!