First of all, let me tell you that you are not alone. Everyone is first scared when diagnosed. It is not just you.
Second, IT IS WORTH FIGHTING. I truly believe that things happen for a reason, and even though it is tough you can emotionally be stronger than you ever have been.
When I was diagnosed I was more concerned about how the diagnosis will effect my family and friends, not how it will effect ME. It sounds like partially you are worried about how it will effect your family, and let me tell you right off the bat YOU ARE STRONG FOR FEELING THIS WAY. I can tell you care about your family, and you will get through this fine. The first step is thinking positively, and not taking each day for granted.
Start to take some time to yourself. The key is turning yourself around so that you can be stronger than ever: mentally and physically. Read, work out, learn to meditate, practice with memory games, enjoy life. Concentrate on what you can control, and know that by taking control of everything else in your life you will be the winner in the fight against MS.
Here is an article to read about morning routines. Hopefully that will help you start. http://www.aworklifebalance.com/morningroutine/
Good luck, keep your head up and stay positive.