what is going on??

I have not had a period since May 25th.. I took tests and they are all negative. I have pregnancy symptoms (I have two kids, I know how my body reacts to pregnancy). I gave up on the idea of being pregnant because of negative tests and now I'm wondering if I have cysts or something else I should worry about. Last night 8-26 I had some very dark brown watery bleeding with little tiny clots in it and it continues through the night, today the bleeding has turned to a brighter red color.. Wierd period or is something else going on?