VFL or leftover hcg?

Hello, after extensive research I've learned it is possible to still get vfl up to 1 month since miscarriage and not be pregnant. I am 29 days since the start of my miscarriage on 2/3. I had blighted ovum and had to take misoprostol. I ovulated on 2/23, I knew based on symptoms I was experiencing and always experience during ovulation and it matched the app. Had sex on 2/21 prior to ovulation and about 3 times prior to that. So i guess my question is how common is it to get vfl 1 month after miscarriage? And is this even a vfl or an indent? Help...