I don't know if this will be helpful or not but when I was on the pill I stopped once for about 6 months and when I went back on the exact same thing happened - it was like the pill stopped it. I hadn't had a baby though so don't know whether it is the same thing for you. So if I was in your situation I would not have been surprised if this had happened as it had happened before, and would keep taking the pills but again I can't say whether that's the right thing for you to do.
Sorry that's probably totally unhelpful!! If in doubt I would make an appointment to see a nurse at your GP's surgery.
C