So sorry for your loss. Sounds like Tessa had a good life and like Wolfstraum said, she was where she wanted to be.
Don't beat yourself up, sounds like there was nothing you could have done. We lost ours at almost 9, the youngest ever. I beat myself up for a month or more thinking there was something I could have done. Now I've come to realize, she had a good life and was happy. Nothing I could have done would have changed the outcome.