Oh dear! I can barely see to type because I'm tearing up so bad.
I know you think that there is always something more you coulda, shoulda done (I know I have that guilt with Timber), but in reality, his time had come. He will be waiting for you on Rainbow Bridge, rest assured. In the meantime, you have Ruckus who needs and loves you too. Enjoy him every hour, every minute. He's lucky to have you too!