In the words of 'Finding Nemo'.... just keep swimming.
I am so to hear that you are grieving. It's little wonder that you feel overwhelmed with everything that is going on
Sometimes I just focus on surviving each hour at a time. On a bad day I try to think "well done you survived yesterday" to myself, to help me have the confidence to keep fighting, so that I can have that same positive thought tomorrow.
Good luck - I know only too well how hard it can feel