Crisis of Faith

I think that even the best Christians have crisis' of faith at times. The past couple of weeks, I have been stressed with school and preparing for competition, so the devil has been using all of that pressure to make me doubt my faith. Sometimes I feel that God isn't near, or just doesn't care about me, and that has been nagging at me for a couple of weeks. 
I also recently found out that I have the onsets of Carpal Tunnel. When I heard that, my spirit kinda fell. I mean, I already have so much pain with Hyper-mobility Syndrome, hearing about another problem that would cause pain just made me mad. Writing and typing is a huge part of my life right now, what with school and my hobby of writing, that I thought it was unfair that I would have to do both of those activities in moderation. 
So as you can see, I was beginning to question whether or not God really cared about me. But serving God is everything to me, and I don't want to spend any part of my life away from Him.
I just have to trust God, that He knows what is best for my life, even though I don't understand everything that is happening.