Welcome @Andrea_J1 It's perfectly reasonable to be absolutely terrified. I lost my sister to this disease nearly 20 years ago and I felt like my world had collapsed when I was diagnosed. This forum has helped me through some of the worst periods of my life and given me some great laughs as well. As you move into treatment, you should find that you can regain some stability as you focus on what has to be done.
I had the genetic testing and it came back as negative for the known but will be reviewed as future discoveries are made. The geneticist was pretty convinced that there is something going on but it could just be that my sister and I are an unfortunate coincidence. For me, it doesn't really matter as that horse has bolted, but it may be useful information for my kids.
I can't comment on bilateral as I had one breast affected and chose, on surgeon's advice, not to take the other one off. I had a wide excision and sentinel node biopsy followed a couple of weeks later by a mastectomy and axillary dissection once the path report came back. I needed some help with some things for the first couple of weeks? (anything that I had to reach for such as hanging out washing) and I would get help in the first few days at home with getting in and out of the bath (more as a safety thing rather than a need). The time frame is just a guess because it's a bit of a blur, now. I'm a librarian in a school so my job involves a lot of reasonably heavy lifting and reaching. I took the active treatment time off due to the impact of chemo but also because of the manual aspect of the job. I have been back at work now for 7 weeks and I know that I do not have the same upper body strength that I had before but hopefully, I'll get there.
Come and talk to us when you want to - there's usually someone around.