Yep, major injury sux
Had a few big setbacks over the years, including a life changer in 2009 that now means i am permanently restricted in what I can do. It also meant a solid 4 months out of the gym completely, and being 100% sedentary for that time (bar specific rehab work).
All I can advise is to take a breath, and accept what has happened. Then from there focus on what you may still be able to do (a broken arm wont prevent you keeping your cardio up by using a stationary bike for example), and also to use your downtime to prepare and gen up on rehabilitation strategies, so you can get the arm back to full function as quickly as possible.
The bright side is that to regain a level of physical ability is always quicker than to attain it in the first place, so keeping your head now, and rededicating yourself to your training when able, will ensure you are back where you want to be in a shorter space of time than you imagine is possible right now