As someone who suffers from Mental Health issues, I can tell you that what you just did here is positive. Things happen in life that are not in your control and you have to make the best out of what hand you are dealt. This is why it is important to celebrate the little wins just as well as major victories to give you anchors along the way when bad things happen.
I really do hope for the best outcome for your mom, as I am sure most of us here do as well. You have to remember to take care of yourself though. You can't help anyone else if you are unable to help yourself. Something that has taken me quite a while to learn...
Perhaps later down the road, you might feel up to putting a little buddy for the MC to interact with that pays homage to your bunny. I have had many experiences in my years dealing with the inevitable annihilation that waits to greet us all and the best way I have found to cope is to find some way to immortalize memories. Be it simply visiting an area that used to be our spot, to making a prized dish from a passed on recipe, little things help us remember the good times and can give us that little shoulder we need to keep moving forward by providing a great memory of better times.
Here's hoping you can find some happiness and that you get to feeling better.