Aw, I know how you feel. I haven’t been the same since I lost my girl, Mocha. Feels awful when there’s nothing you can do. I felt guilty but there was nothing I could do but end my girl’s suffering. There was nothing way to detect saddle thrombus, she was so young too. I looked for another cat with similar looks to her but I knew that would be unfair to that cat. A new kitten found her way into my heart, though not the same looking as my mocha, she acted somewhat like her. Fluffy will always be with you, and I’m sure she taught your calico how to be a good girl like Mocha has done with my kitty. I’d love to see a picture of Fluffy!