Cycle Days after miscarriage 🤔

So I’m really confused on this whole cycle days after MC I thought you had to wait till your next period to count cycle days but someone said I was cycle day 12 since it’s been 12 days since miscarriage which was may 27 but I bled from may 27-29 and spotting till 31st my hcg was confirmed 0 may 29th , I haven’t had a positive opk yet my cycles ranged 28-36 days before miscarriage, I’m so confused ladies can you please help me out and explain it to me I’ve literally been doing 2opks & 1 hpt a day cause I don’t wanna miss anything