Implantation bleeding or just starting my period?

I had light spotting yesterday and today, it’s a little bit more than yesterday but it’s not same as my usual period....

I had my D&C last February 19 due to blighted ovum diagnosis and had my first menstruation after D&C last April 8. According to my calendar I should have my period starting May 10 but I was already 6days delayed before yesterday happened.

I’m a bit confused because me and my husband had sex after my ovulation period (based on my calendar) and a week before my forecasted period.

BTW, My menstruation is irregular since then that’s why I’m totally confused.

Comment anyone? Thanks in advance!