I am having some female issues, and am wondering if anyone can help me?

In February I started what I though was my period, and here it is June and I am still on it.. I think I may have been off of it a day or two here and there, but mostly on it the whole time... I have been bleeding extremely heavy at times, where I would fill 3 pads with in a hour. I went to my regular Dr because my OBGYN wasn't in last month, and she did a pelvic sono and discovered my endrometrium is abnormally thick.. So she referred me to my obgyn for the 21st for a biopsy.. This past weekend, I have had A LOT of horrible cramping! And the past few days, I have had pain that radiates from my uterus to what feels like my ovary (not sure tho) and my belly feels tighter than normal. I took a pregnancy test and it was negative.. I am really freaked out and my dr can't get me in any earlier.. Any suggestions on what it could be?