its still here 12 days later?

I have been on the pill for 2 years now and my b/f and I have recently decided to try for a baby. When on the pill my cycle was every 21-24 days and lasted for 4-6 days. I did take 3 pills from my new pack but then decided to quit and ttc. I got my period 7 days after stopping and its still here 12 days later. Started off normal and got lighter as the days went on but it hasn't stopped yet. In fact this week its heavier than normal. I know my body will need time to adjust after being on the pill for so long but I expected more it to be more intermittent rather than period lasting 12 days!! I have no pain at all, in fact it doesn't even feel like I'm having a period. I am a little worried about it as I am afraid that the pill may have masked some underlying problem I may have had previously. I would be grateful for any advice. Thanks in advance.