just got post mortem, it was her spay that caused it, she was completely infected on her uterine stumps, it had spread else where, her guts were all closed and stuck together. Gemma(vet) said that even if she had had surgery in an attempt to fix it, they would have euthanised her on the table, there was nothing that could have been done.
She also said that it doesn't happen that often and it is the first one in four years that she has seen
It makes me feel better that I did do the right thing in ending her suffering.
Bringing her home tomorrow for Charlie to see, then we will bury her in the garden.