Help confused with AF after mc

Laura • 2 lovely children ttc #3. Had 2 MC this year so far.
Hi I was 5 wk and had a chemical preg on 12th feb bled like a slightly heavier than normal period but still waiting now 4 wks later for AF took a test today and it was bfn how long should I wait to see if AF arrives before ringing dr I'm 36 so worried about getting pregnant again 💗