I was sidelined by a broken shoulder the summer while I was training for the Marine Corps Marathon. Got depressed, too. It's normal.

Focus on recovery. Also, you can still be active---walk! Focus on the long-term and remember that this is temporary. You'll be back on your bike, and stronger than ever, before too long.

Something to keep in mind is regaining strength and range of motion in your shoulder. When I finally was able to take off that blasted sling for good, I could barely raise my arm over my head. It's amazing how quickly muscles can atrophy. Even if it hurts like XXXX, move your arm after you get out of the sling. I forced myself to do that after I broke my shoulder and later, after I broke my elbow. It was horrible but I'm glad that I did it.