Hi Heather,
I know exactly where you are. I was devastated when Kevin was finally diagnosed. It rocks you to your very core and there are so many emotions all at once that you really feel like you're going to explode. Allow yourself these feelings for a day or 2, then buckle up and get ready for the battle. You will be amazed at how strong you are once you are under way and know you are now ridding his body of the cancer.
We had just adopted 3 siblings from the foster system 2 years before diagnosis, so I understand the worry for your child too. One thing I would say is don't say Daddy will be fine when they can see he obviously isn't fine. Our kids were older and more involved, but, of course at 6, they won't understand all the technical stuff. Daddy's just going to be sick for awhile. At least that way when he looks like heck for a bit they aren't too scared because they were forewarned.
I found that family was NOT the place to vent when we were going through this because they were as frustrated and scared as I was. I would cry in the shower, then put my warrior face back on and go at it.
Everyone will tell you to try to take time for yourself. That is a hard thing to do, but what I would recommend is coming on here as often as you can and get your boost of fellowship and encouragement. I didn't find this site until the end of our tx. It was a Godsend to me to KNOW others understood.
Lastly, let those who offer to help, help. Make a list of things that you need done and let them choose something. Let them order a pizza. Anything that makes them feel like they are contributing. Don't be surprised if some of your closer friends tend to stay away. They can't handle it and don't know what to say. Try not to take it personally.
We are here for you. Hang in there.
Blessings,
Kathy