TW: miscarriage

I found out I was pregnant on July 8th, started bleeding heavily on July 27th, went and got it confirmed that i miscarried. Fast forward, I have not received a period. I spotted back in September for 2 days, only when I wiped, and have yet to have anything since. I had blood work done about a month and a half ago that showed I wasn’t pregnant, and I took a pregnancy test 3 weeks ago which was negative. What is going on? My OB doesn’t seem concerned at all, she says “everyone’s different.” Should I take a pregnancy test again? What could be causing this other than pregnancy??