My wife broke her coccyx a few years ago in a white water rafting mishap (note: always keep butt up when geting sucked down rapids) and it seemed to take her months to really get over the pain. The bruising in that area was really bad though. Like others said, her doc just said let pain be your guide. I would think you could swim and if you arms get tired maybe do lots of kicking sets to give the legs some work. Good luck…that is painful injury for sure.