Any Idea What Is Wrong?

Okay, for starters i know i need to see a doctor and i am going tomorrow morning. I have already been to the ER twice in the last two weeks and they have said nothing is wrong. I have been bleeding for 20 days. I have had the lightheadedness, nausea, fatigue… which im sure is associated with losing so much blood. But, a new side effect started yesterday that is concerning me. I have been getting the most horrid headaches and i have this extremely sharp pain that will hit down in my pelvic area and it radiates into my lower back from right under my rib cage down to my tail bone. that entire area of my back tenses up and it feels like i have had the breath knocked right out of me. It is really painful when it happens and i am just curious if anyone has any idea what it may be.