Bleeding during sex 37 weeks


Soooo this may be tmi but I am desperate for answers. My doctors are by far the most useless people on the face of the earth.

My SO and I had sex and I started bleeding all over him, (this happened twice before at 35 weeks but only spotting) this time I went to the bathroom and passed 2 huge blood clots and had bright red blood running down my legs. I only bled for about 6 hours or so after that, but I was just wondering;

What may be the causes?

Is it normal?

What could the bleeding mean?

and any other answers will help! (Please no rude comments)