TMI - Mid-cycle bleeding

Hi all. I just have a few questions about mid-cycle bleeding (break-through bleeding).

A bit of background first:

I was on the Levlen Contraceptive Pill until sunday just gone, and had been on it for 1.5 months, prior to that I had been on the mini-pill for almost 4 months. I have never had any breakthrough bleeding and according to my doctor all my hormone levels are fine.

Tuesday last week at about 2pm I started bleeding. It was only light and I didn't need a pad until a few hours later when I started to get some really bad cramping down the lower, central area of my abdomen. My first thought was that I was having another miscarriage, as the pain was very similar to when I had the miscarriages, the blood was bright red and there was some pale pinkish fleshy material.
I had had some rather nasty back pain, only at night, since the previous saturday, but hadn't though anything of it as DF and I had been busy moving things around in the shed - I thought I had overdone it a bit.
When I had been bleeding heavily for 3 days and the blood was still bright red I decided to go up to the ED, where they did pregnancy tests - which came back negative - and general bloods - which were all normal bar my white blood cell count which was slightly raised, but nothing to be too concerned about. I was put on panadeine forte to control the pain and prescribed antibiotics as a precaution.
I have been up to the ED twice since then and seen two doctors who weren't able to find out what was wrong either. One doctor suggested that it could be a fibroid, or a ovarian cyst that has burst - especially as I have a little bit of abdominal tenderness - and has advised that I get an ultrasound and try to get a referal to a gyno.
The only problem is that the earliest booking for an ultrasound that I could get is tuesday next week, and there aren't any gyno's in the area that are available or that I trust (the only female gyno in the area tried to give me aspirin, which I am allergic to, two days after my c-section AFTER reading my notes which clearly stated that I had an allergy to it).

It has now been 8 days, and I am still bleeding. Every second day the bleeding will become lighter and I start to think that maybe it will stop, and then the next day it gets heavier again.

I'm just wondering if anyone has any thoughts on what it could be so that I can enquire at my next doctors appointment and maybe get a little closer to solving this problem.

Thanks in advance all.