Well, even though it's somewhat frustrating to do this, I'm going to be changing my exercise regimen once again. I've been experiencing a little more tweakiness in my legs and back, and I'm forced to conclude that it's probably due to P90X and my body not being quite ready for it. That's disappointing to me, but better to play it safe.
So, it's going to be back to running for a while, as well as working on abs and flexibility. As long as I'm still moving, it's all good.
For those of you who might also be struggling with various things exercisey, I hope this can be an encouragement to you. Don't be afraid to back off of something if it's proving too strenuous for your current level of health. Having to stop entirely because of an injury is no fun at all, and it really doesn't do you any good.