Implantation bleeding or ?

Hi I m trying to conceive. Just off northisterone pills 28 days cycle. Last menses was 25 April bled for 6 days. Did the deed last tue and Fri PM. I tested clearblue digital smiley face on 9th and 10th of May. Is it likely to conceive. We didn't do on ovulation cause hub was very sick and couldn't stand. Then 12 may evening there was like a big coin size of brown blood or two small coin size of brown blood and a bit of cramping. 13 may got some 2 to 3 small coin of brown blood. Is this ovulation bleeding or implantation bleeding or? Its CD 19 today 13th May. Please advise#pleasehelp #advicepls