You are right shorts and tennis shoes hurt in an accident. Biggest adjustment that I will incorporate when healed is jeans all the time and boots even on short trips and now a helmet. Tennis shoe gave and my big toe was almost ripped off.
Dang man, sorry to hear that.
When I was still in the Air Force I taught a lot of Rider Safety courses. I stressed to these guys in ever course that safety equipment was a must, and never drink and drive. During my time teaching there in Japan I watched a few of my students ignore everything and pay the ultimate price.
One kid finished the class on Sunday afternoon and I signed his license so he could ride on and off base. He celebrated with a couple of friends, and went riding off base after drinking at the NCO club. After a couple of short stops he got sick of putting the helmet on and off, so when he hit the side of the truck 5 minutes later he had no protection. The final report was that he was legally drunk, and that based on the impact a helmet would most likely have saved his life.
The other story that always comes to mind is even more sad in some ways. The rider was a good kid, and he was in full protective gear. His girlfriend on the pillion was in light summer wear only. She died at the scene, he was a broken man, and he was charged with the Japanese equivalent of Reckless Endangerment. In Japan a US license makes us what they term a professional driver. That means the penalties are more sever, and in most cases the pro driver is at fault because they should have seen and avoided the accident.
So not only keep yourself safe, but anyone you allow to get on the bike with you.
Heal up quick man. At least you were smart enough to learn something from your mistake, and at least you are getting the chance to learn it. Best wishes.