Is it too soon??

Last night I got into a car crash. And when I told my SO he was really worried but as soon as I told him I was home from the hospital and safe, they were just checking for any injury. I am fine, but he plans on coming over today and have sex but I really just wanna lay in bed. But today we planned on doing it for the first time, my first time, now I don't want to. What do I tell him??