Please help

Hey everyone. I had two positive tests on Friday (2/15) then another much darker positive on Sunday, which was the day my period was due. Well, today I have started cramping and bleeding, so I’m assuming I am experiencing a miscarriage. I had one back in 2015 so I do not feel the need to go to the emergency room. In the midst of the bleeding starting, I decided to take a dollar store pregnancy test and it came back completely negative. Does this mean my levels are already back down low? Do I count this as a period on the app? How soon did it take for you guys to conceive after a miscarriage? (I was been 4 weeks 3 days)