Menstrual cycle lasting longer than a week

Kaela • I`m a 21 year old woman who is now trying to have a baby! I have to take clomid to help me ovulate due to Endometriosis and irregular cycles. Hope it helps! (Just started it)
So I'm on my 8th day of my cycle with very heavy bleeding, and this has never happened before. I have a history of endometriosis and cysts since I was 17, I'm 21 now. I'm TTC, and this cycle actually started on its own to where before my doc would prescribe medication for me to start a cycle. This cycle has been the worst for me with the worst cramping I've had in my life, and it's constant cramping. My cycles are normally 3 days so I'm a little worried about all the bleeding, tissues coming out, and severe cramping. Any ladies have this happen before? Any input would be greatly appreciated! (I've called my OB nurse and I have to wait till tomorrow to hear back from her)