Need help with deciding if I have my period or remainder of MC

Without having to write a novel about the very prolonged Miscarriage I am having . The doctor has been following my levels down to 0 . There was a fluke in one of the tests where my levels went from 11-12 so he decided to to an internal US . Needless to say I ended up continuing down to 4 this was last Tuesday’s # .he mentioned I just had some leftover fluid but nothing concerning it would finish up on my next period . Today I have what seems to look like a period with a tiny bit of thicker darker spots on the pad . Now getting to my main question ... would you think I could get my period within 1 week of last seeing my doctor ? Or is this likely the remaining fluid I had ? I am asking because I am supposed to letrozole on the 2nd day of my period but I literally have no clue if I have a period or the finishing of a miscarriage I don’t want to take the pills and waste them if it’s impossible to get a period so soon after levels dropping