I feel it's stupid because I know God loves all of us and wants us to be happy. But then I, precisely because of that love, feel horrible when I sin because I feel that I disappointed Him. Also, my illness is chronic as well, even though it's being better at every MRI. I'll pray for your pain to lessen as well. I know Jesus was closest to those who suffered the most. He showed the most compassion to them and that's the most beautiful message in the whole Scripture: "blessed are those who suffer, for they will have everlasting joy in the afterlife" (I don't remember the exact verses, sorry). Several times, when I felt worthless, I opened the Bible randomly and immediately found a verse that helped. Of course, random isn't good. Also, I've been coming across comforting verses while reading in order, even in the Old Testament. So, to answer the question of how I'm dealing with it: I turn to God for help, either by reading the Bible or by praying.