Man, sorry to hear that. Yes, it's a solo sport, but it's much better to ride with buds. I don't get on any rivers above class III without my friends. Making sure that you and your friends have good first aid training is a plus too. I've put in two dislocated shoulders on the river in places that you just can't walk out of. Mountain biking brings you to those kind of places sometimes. I took a two-day course in wilderness first aid about 5 years ago. While I'm a little rusty, I still remember quite a bit from that class and I've been able to help out several buds with serious injuries ranging from concussions to shattered ankles. Just something to think about. Hope you get well soon. I feel like such a wuss compared to others' on this board with bigger injuries.
http://www.nols.edu/wmi/