Stress Fracture please help

Was it diagnosed as a stress fracture?  If so, running on it is only going to make it worse (as much as you don't want to hear that....).  I had one earlier this year (third metatarsal) and was unable to run from the end of July to almost the end of October (tried a handful of times in between and it still hurt, so I stopped).  

That said, I was able to maintain my run fitness pretty well by aqua jogging my butt off.  If you're willing to aqua jog (maybe after your swim workouts), you could still be ready to race in March, but don't rush running -- it's only asking to have it go from a stress fracture to an actual break. 

"foot pain is ubiquitous with running"??  I don't know what you're doing, but on any given (un-injured) day, I don't have foot pain when I run.  Likewise, I don't have ankle pain, knee pain, hip pain, or any other pain.  And, personally, I would not suggest anyone run through pain (real pain).  I've tried....in fact, when I had my stress fracture, I tried for a couple weeks to run through it.  I distinctly remember a 70 minute run I had on my schedule, getting about half way into it, and realizing there was no way I was going to continue.  I had to walk all the way back home and finally come clean and admit the fact that I was injured.

OP -- my original suggestion still stands: aquajog (here's a good set of workouts: http://rw.runnersworld.com/rt/pdf/Nine_Week_Recovery_Plan.pdf) and try running again in 4-8 weeks.  A doctor is probably going to put you in a walking boot, which may well speed up the recovery since you won't be stressing it further.