Coming off the pill to TTC

Hi,

So I came off the mini pill on 14 November. My last period ended on 4th November. I’ve had all the pregnancy symptoms under the sun which I think is normal when you stop the pill. However I have only had a day of bleeding on the 10th December that wasn’t really a bleed it was red cm/blood when I wiped along with cramps then nothing until today 15th December I’ve had brown spotting once when I went to they toilet and then pink cm in the afternoon with little cramps/pain. Is it possible I’ve ovulated late and this is implantation? I’ve tested with eBay cheapie and negative! I’ve been so tired, cramps I’ve had awful headaches and heartburn! I’ve already got a boy who is now 15 months. Anyone else experienced this?