Tamoxifen for estrogen dominance/prevention

I was recently prescribed tamoxifen for estrogen dominance. I’m 35 have 2 kids (don’t plan on having more) I gave a bad history of cancer in my family. My mom had breast cancer recently but luckily caught it early My grandmother and great grandmother both passed from breast cancer. Amongst other cancers from other family members. I have adenomyosis and hashimotos. Can anyone give any insight about my situation? How they did taking tamoxifen with my same issues? Thanks