RIP Bear. Just remember all the love and joy he gave you and that he felt the same way.
I had a similar experience with my beloved dog who died two years ago...
My black lab started to swell up in her stomach like a balloon. When we took her to the Vet they found that she had hepatitis. They said she had about 3 months to live. We had to give her a ton of pills everyday and it broke my heart because I knew it was only delaying the inevitable. My sister was trying to come home to see her one last time, but she got far too sick so we decided we were going to put her down. Every night, without fail, she would come upstairs and sleep on my parents bed. One night, my mom woke up in the middle of the night to go to the bathroom, and then went to find my dog when she realized she wasn't on the bed. She was at the bottom of the steps - too weak to make it upstairs. My mom woke up the whole family, and we went downstairs to see her. A minute or two passed, and she started really breathing hard...ragged, heavy breaths. I started to hug her and hold her and she died in my arms in the middle of the night at the bottom of my steps. I will always believe that she was holding on and fighting until my family arrived so she could leave us while we were there. She was only 7.