First miscarriage & looking for advice

Erin🏴󠁧󠁢󠁳󠁣󠁴󠁿 • 3 years TTC #3 Mum of two little heavenly stars 💛💛🦋🦋

I found out on 23rd of June I'd lost my baby, 8 weeks and 4 days, Found out no heartbeat. I waited to miscarriage naturally, took my body 2 weeks to start any kind of bleeding, passed baby, lots of blood, went to brown to stop, Went back into hospital on 14th July to remove very infected blood clots stuck in cervix bled heavy for two more days and stopped. How long will my body take to restart a period? Can I start taking prenatal again? Any specific testing I can ask for? I've had two very preterm births now, one resulting in the death of my 7 week old daughter last year so really make me think somethings wrong with me and carrying a baby, as much as health providers say there's not? Help, I'm so confused and just dying for something to restart, already getting neg tests on pregnancy tests so everything I think completed.