Firstly, it sounds as though you are all grieving. Grieving is hard and everyone deals with it in different ways.
You are never going to be able to fully focus or have the energy if you, yourself don’t get the emotional support you need.
Secondly, speak to your children’s school to see if they can help with any support their end. They can start the process to refer you for a EHA for a family worker, which can open up other external agencies for help.
Finally, I really hope you are ok, you will get through this. When thing become tough for me at home, I have found writing to my children helps . They always write back and sometimes it’s easier for us to vocalise our feelings and work from there.
Take care x