TW miscarriage

TW: Miscarriage***

I had a miscarriage from the 7/6 til the 12/6 so the bleeding only lasted 5 days, I was only 4 weeks so I miscarried roughly when I'd have my period anyways (more of a chemical pregnancy but doctor's still classed it as a miscarriage) so I'm trying to work out when my next period would be, my HCG dropped straightaway, i wanna take a pregnancy test this month again just to see if I've fallen pregnant again but can't work out when would be the best time to take one, I'm also 80% sure I ovulated 5 days ago x