Falling Apart

So here's the situation. I stepped up a few months back and signed up for IM Arizona (4/9/05). 10 months is plenty of time to be ready, right? I highly respect the distance but it doesn't scare me. I have a running background but have done more biking than anything this year (about 6000 miles this year). My swimming is terrible but I shouldn't have a problem making the cut-off. Even though I've been stepping myself up very slowly and doing lots of base miles, I'm starting to fall apart. I have a knee that swells a little after every run, more if the run is longer. I have a shoulder that likes to pop. I pulled my lower back last weekend at the gym and had a hard time carrying my gym bag to the truck. And I'm not very fond of how my feet are looking these days either :-)

Since I'm coming into the bigger and bigger weeks, I'm torn on what I really want to do. Part of me says this is just part of sucking it up for the IM. Part of me says to blow it off and live to try it again another day. Part of me says, you told everyone you were going to do it so don't wimp out now. I've decided not to make a decision until after the first of the year regardless.

Any thoughts?