After you left ER, did you check with your own surgeon about what you were/are experiencing?
Bleeding can be normal for around 4-6 weeks. As one increases her activity level, bleeding can sometimes occur as new areas are a bit irritated and tender, "scabs" come loose, etc.
Bright red bleeding that fills a pad an hour is a cause for concern and one should seek medical attention in that situation. If bleeding is also accompanied by new pain, fever, etc. one should check with her doctor.
Try not to panic. You did the right thing by seeking medical attention. If you still have concerns, do not hesitate to go back to ER, call your doctor's after hours number, or go to an Urgent Care facility.
Sorry to hear you are having problems. Let me share what happened to me. I had a TAH back in August. I had no discharge upon coming home from the hospital then around week 3 post op I started spotting and light bleeding. It would stop at times and then start again. I called my doctors office with my concerns and went in to be checked out for my piece of mind. Turns out my internal stitches on the vaginal cuff were fine. Sometimes leftover blood from surgery seeps thru the cuff before it is healed shut. He told me after examing me that it was old blood (dark wine color) Said if it were bright red that would mean new blood more of a cause for concern. Also I was experiencing cramping and discomfort at that time and would feel relief when the blood passed thru. I also asked at my appointment how long could I expect this to last. Told me could be week to two weeks. I ended up only having it for a week. I am now just about 7 weeks post op and no more bleeding since that time. I saw my doc again about a week ago and my stitches are completely healed and disolved. (Hurray) Best of luck to you in your recovery.