Hi Char, I have not been exactly where you are but a close situation at the beginning of my journey. Like you I was having a hard time concentrating and taking care of business when my mind was in a loop of worry and decision making. This is a very difficult thing.
I have learned to give myself time to worry once or twice a day for 30 minutes, then if I start obsessing at a different time, I can say nope, I will think about this during its time, this time is for something else.
I also would applaud you for what seems like a very rational and well thought out decision of going with lumpectomies then if cancer is found move ahead with mastectomies.
I hope you can likewise think about endocrine therapy in this way. Keep an open mind and get as informed as possible about why exactly the doctors are recommending it for you. Because you are younger than most of the people who have to make these decisions, you have more to consider about quality of life. You also have more years to live with the decisions you make or revise them as necessary. I am quite close to your age, just a youngster.
Do you have a list of questions for your doctor, about surgery? How about in reference to endocrine therapy?