Is it possible to get a miscarriage without even knowing you're pregnant? i was 10 days late last month too, very heavy and painful period . So just wondering

The only way to know is if you had a positive hpt previously or if you get a quant level blood test. In my own experience, someone my cycle is just heavier than other times. When I did have a confirmed chemical, af wasn't even as heavy as my cycle this month, which was definitely not a chemical.