The best I can do

I had no intentions to write another post about the marathon after last week, but turns out that it taking up 90% of my thoughts these days so here it is.  
My knee continues to bother me and I haven't had any improvement the last few weeks.  I've been icing, stretching, resting on repeat and I am still struggling. I've tried KT tape, a brace and multiple chiropractor appointments.  The few short runs I've done the last three weeks ended quickly as my knee hurt pretty badly.  I haven't fully "pushed through" to run because I figured that I'd save any of that for the race day.  
My emotions are mainly just mad.  I feel like I trained so hard, put a huge amount of energy and time into the training and have a hard time not feeling like it was wasted.  I ran faster than I did the other marathon training times and was feeling confident that I would beat my last times by a decent amount.  Now just the thought of finishing seems somewhat impossible.  I'd say stubbornness and determination are one of my top characteristics, but I truly don't know if I'll be able to finish.  
I feel like I've lost all of my mental endurance and even without knee pain I can't imagine running 26.2 miles. My mom thinks that I shouldn't run the race, and that quitting once I start would be harder than not doing it.  But I don't think I could handle not trying.  However, the idea of walking off the course just about kills me.  
In situations like this it is hard for me not to be mad at God, as this seems like just an "easy" fix to heal my knee even if just for race day.  I have a hard time understanding why he would allow this to happen when I've worked so hard.  What I forget is that there are probably countless times a week he protects me from injuries, suffering and who knows what else.  I don't know the times he's saved me from a car accident or protected Addilyn during a fall.  I don't think God picks and chooses what he heals us from and doesn't, but I do think that He allows us to go through hard things to teach us something.  I know life isn't perfect and can't be easy all the time or we wouldn't constantly be needing to reach out to God for help.  
So while right now I'm frustrated and beyond disappointed, I want to trust that God knows everything, even things like my knee pain and how hard I worked for this.  And I want to know that I can get over this and move on and just do the best I can do and be okay with the outcome.  Want is clearly the key word as those things are currently not coming easy for me.  
I'm going to show up on Sunday ready to do the best I can.  To suck up my pride and know that if I don't finish that's okay.  To be proud of myself for all my training and discipline and to know that it wasn't a waste of time.  To remember that despite all the work I did to train, the marathon is just a race.  One race.  One day.  And not any definition of me.