Back friendly exercises

Sandy • married to the love of my life, suffered a MC 8/27/14 but we are trying again. My 2nd his 1st
I was recently diagnosed with disc degeneration and arthritis in my back. Was told core strengthening would help take pressure off my spine as well as loosing weight. I gained weight from a failed pregnancy and haven't lost it. So, does anyone have any suggestions on back friendly core and cardio exercises. I don't want to cause more harm than good.