My best friend, B. Lee, died today. He was 5 1/2. ?

I rescued my friend 4 years ago. Our love affair was instant. I don't know what happened. Apparently, my shrubs are lethal. We have lived here for 10 years! We've had 4 dogs! 2 dogs at a time! wWhat the F**:( I can't help, but feel to blame. He's my responsibility. I let him down. i feel damaged. Lost. Need help...