Anyone else have extreme blood loss with this condition?

Hi all, I thought I'd ask as my doctors seem to ignore this part. If I'm not on antibiotics (which im told wont help but definitely do) when I have a BM, I bleed like FUCK out of the hole. Like I mean whole bowl turns red type. But once I'm off the toilet its as if nothing happened, no pain or more bleeding or nothing. I'm wondering if anyone else experiences this, and what might be causing it?