What are the first steps that I need to do following my husband's death

My husband passed away Wednesday. He had a heart attack on the 12th and never woke up. He was my entire world! I'm having a hard time processing growing old without him. In order to function, I need to stay busy. Thankfully, we have one child still at home, so I'm not all alone and it's mandatory that I don't just fall apart.

My adult children are helping plan the Celebration of Life and I have an appointment with the cemetery where they will handle burial, death certificate, etc. What are the basic things I should be doing? I was a SAHM so I know I need to figure out health insurance. Is there something you wish you knew right away or something helpful for me to know?