No, don't go there. True the initial investment can be high, but it levels out, unless you're a gear hound like me
It sounds like you've really thrown yourself into training for this tri and the MS150. Going from very little running/no cycling to what sounds like a heavy schedule.
My opinion - back out of the race(s). It's not worth the damage. You've gotten and can still submit your pledges for the MS ride... that is, after all, what matters... the $$ to get the research to find a cure.
I rode the 2000 AidsRide injured. It was 2 yrs before I could ride again.
Back off - rest, yoga, ice and then after a couple of weeks come back SLOW. An easy 3 mi run. An easy 10 mile ride. Concentrate on the swim thing for a while... it's non impact, non-weight bearing. Do that simple, easy stuff for a couple weeks... then increase either the bike or the run by 10%. The next week increase the other 10%.
Set a date for an event further out in the season... if you break your body down too much, you won't be fit for any fun.
spazz, who really understands the frustration.