Just found your post! I've had this for nearly 16 years now, and it has put my life on hold completely, have withdrawn quite a lot as I'm either having my period which has got increasingly heavy (I'm now 52), or I'm in pain for week 2, and when the pain goes it's such a relief then I need to recover and get my strength back for a week or two before it all starts again. I don't want to plan anything like trips or outings or holidays ahead of time, I can only do things on the spur of the moment, so I feel I've not got anything to look forward to! I'm only waiting for my menopause as I'm hoping it will go when I no longer have the hormonal rollercoaster I have now. I will not have surgery as these often do not work or are only temporary, and I refuse to have a hysterectomy. I know I have many fibroids in my uterus, so I have always thought as it's week 2 and the oestrogen rises in that week that it was related to this, as I think this prompts the fibroids to grow. Although my pain is very low down (supra-pubic and over to the left ovary) I wonder if it is internal bleeding collecting at the bottom of the pelvis as one of the other posts wrote?
I also have had an ectopic pregnancy when I was 36 and the pain usually seems like it's around the scar so I wonder if adhesions and endometriosis are also possible. However, I will not go to the doctor just to get either drugs or surgery, so I feel a bit stuck with it all. I hate taking painkillers too, but end up taking 2 nurofen when I can't stand it anymore. I've had to take two doses twice since Saturday, but it does start to drive you mad, I agree, you can't think straight, and I also end up breathing really shallowly with the pain, I simply want to not be in my body!!!
I hope you're ok with your situation? I don't think doctors have the answer frankly, they can't solve the problem without giving you other problems instead, which is no good to me...