It is frightening and overwhelming when you get the diagnosis, but once the roller coaster of treatment starts you really don't have time to dwell on it - you are so busy with appointments and information and getting surgery/chemo kits ready.
What a wonderful role model you have in your Mother - 18 years past treatment, which was no-where near as advanced then as it is now. You have great genes to fight this thing and win!
Don't be afraid to accept help from friends or other mothers at the school - people will want to help you and maybe won't know how, so you could suggest pickups or dropoffs, meals, help with cleaning, etc. Your husband sounds wonderfully supportive and you will get through this for him and your beautiful children. It is so good that they have found it quickly and are dealing with it.
All the best - come and chat whenever you feel like it - I found someone is always here and the support is amazing. Sending you a big hug, Michelle xx