chemical and now?! help!

hi ladies. need some help please: had a chemical pregnancy a week before my period (due this Wednesday 21st Feb) and I bled for the past 3 days and this morning only some light spotting (bfp on 14 Feb the bleeding 16 - 18 Feb quite a lot). do a use the first day of bleeding at cycle day 1? so confused and don't know when I will ovulate now 😕