Hi CharleyFarley
It could be nothing to do with the hrt, it could just be a coincidence. I say this as during peri I had very heavy flooding periods, sometimes with clots.
I remember twice I sat on the toilet for hours as there was no point getting up as a few minutes later I had to change both tampon and pad. It was just dripping like a tap, with clots falling out every few seconds.
The second time when I stayed on the loo was even worse, as when I changed tampon and pad, and before I even got out of the bathroom (so approx 5 secs after changing) I could feel it all leaking out, my tampon and pad were fully covered - sorry, tmi, but if it helps you, or others! This was evening time and I spent the whole night on the loo, the next morning went to GP who in turn sent me to the hospital where I was diagnosed with polyps. Had these removed and my periods were never as bad after that.