Breast cancer

I've recently been diagnosed with stage 1 breast cancer and it's also in my lymph nodes,  surgery has been booked for December but im really worried about developing lymphodemia as my lifestyle is very physical,  I also have osteoarthritis in my hips and spine and rely on my upper body strength to do the exercises that keep on to of the pains in my lower body, to the extent that im considering not having breast surgery.

As you can imagine my family and friends think im insane for even considering this, but they respect that it's my body, my choice. 

I feel completely out of my depth with my emotions and im reaching out for help stop my mental health spiraling out of control .