Just because you're at risk of getting a disease does not mean you're going to get it...unless you're convinced you will. Our minds are way more powerful than we realize. Fear of a condition can create or manifest that condition in our lives, so the first thing is to take a deep breath and calm yourself. Know that there is hope and that help is available.
Most diseases are multi-factorial. Breast cancer is one of them. You can empower yourself by doing some research. Holistically speaking, you can approach your diagnosis on several fronts. Physically, you can improve your diet and undergo de-tox with the help of a trusted and experienced naturopath. Mentally and emotionally, you can learn to manage your stress and resolve your emotional issues, including past trauma. Spiritually, you can engage in activities like yoga and guided meditation that can help you deal better with your situation.
Help is out there. You just need to become knowledgeable about what can help, and what support is available in your area. Please understand that a diagnosis is merely an educated guess and not writ in stone. There are many ways you can help yourself. I wish you well on your healing journey.