Early miscarriage

My period was 4-6 days late, tested BFN'S in beginning, then stopped testing. Had a really heavy flow for 24 hours with painful cramping, more than usual, this stopped for 2 days with light spotting & now 4 days later I am having a heavy flow again with cramping and large clots. Has anyone else gone through this. Usually my flow is textbook. Thinking I am currently having a very early miscarriage 5 weeks.