Endometriosis? I need help?

My sister had endo at 23 and ended having to have a full hysterectomy (sp). Here's my background: I am 27 and married, we have 4 kids- 7,5,2,19 months. Well starting last July I have vertigo which seems to be worse when I am menstrating. I had a period last Aug, then not another one until the first week in Dec. It was very dark and heavy and my vertigo was really bad, could barely stand. Then I ended up having another period just a week after ending that one. Didn't have another period til Feb. Then starting on march 17th had just a brown discharge for about 5 days and it was heavy enough for a pad. Then a lil over two weeks ago, had some brown discharge (again enough for a pad not a liner) after a couple of days it got real heavy and dark brown, then was mixed brown and red now heavy red and I'm still pretty heavy. It's been around 15-17 that I have been having this "period". Does anyone know what could be causing this. Just trying to get ideas before going to the gyno cause my husband's insurance through work is very very expensive so we're self pay until we find our own insurance. sorry this was long. Thanks in advance!!