Sarah, I'm so sorry. I have no words to make the pain go away, I can only say that Tuna had a long and wonderful life with you. Every post you made about her showed how much you loved her and how much you did for her to make her safe and comfortable.
Godspeed Tuna, you will always be in you Mommy's heart. May you run free at the Bridge with those who have gone before, there will be a lot of wonderful Angels up there waiting to greet you.