I thought I was going to run yesterday, but will I be pushing myself too far to try and run AND try to complete a half-marathon?

I wonder why I signed up for it. On the one hand, I feel like I won't be able to do it because it's such a long distance and I have only begun to base train.

On the other hand, I've already completed a 10 mile run, (even though I didn't run the entire thing and stopped in the middle to stretch out).

This is the mental anguish I deal with every time I think of running farther.