Bleeding during ovulation?

I need some advice on what this could mean. Me and my partner are trying for our first baby and I stopped taking the pill on the 15th of this month (just as I finished my period) everything has been normal but last night I noticed some pink spotting. I read up on it and just passed it off as normal implantation bleeding but when I woke up this morning I was heavily bleeding and with blood clots and has continued throughout the day. Could it just be from stopping taking the pill or could there be something wrong?