You sound like me!
I did a marathon 5-16-09. I believe I got a stress fracture while racing (no insurance, not confirmed, but it was hurting bad for a good week or so afterwards).
Since I couldn't run, I decided to sign up for a 3 mile swim. Why not? I can go see some family in Maryland and swim!
My swim is July 11th. It's kept my focus off what I can't do... and made me think about what I CAN do.
Good luck on your swim!
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather, to skid in broadside thoroughly used-up, totally worn out, and loudly proclaiming: WOW WHAT A RIDE!!!!"