Make sure you recover from your wounds first. Stationary trainer might be ideal to maintain your fitness but be careful pushing it too far as your body will use some of it’s energy to heal as well.
In regards to the mental aspect. I’ve had a couple of crashes during the races and for me it was more about finding the reason for the crash and determine what I could have done to prevent it. One crash was in a 180 degree turn in the lead up to the finish line with some gravel on the inside of the corner. I wanted to take it quicker than my breakaway companion and took it too fast → didn’t affect me afterwards, knew what happened and why.
Another crash happened when it started raining during a race. This was after a long dry spell. there was some oil on the surface of the road and someone in the front of the pack hit his brakes and a whole bunch of us came down. I found this harder to recover from mentally because every time it starts spitting now during a race I’m much more aware that a crash is more imminent and can be totally out of my control. I even try avoiding racing in wet conditions for this very reason.
I do find that just after a crash I’m a lot more cautious cornering but over time you gain your confidence back and after a couple of rides you corner just like you did before.