Answer:
We should try and honor the pledges we make but under special circumstances it is understood they cannot be met. Try and give a small portion of what you pledged since God looks at the ability and heart to give, not the amount. He will honor even a portion of this if it truly is the best you can do under the current circumstances.
Sometimes sickness is because of sin…sometimes it is just so God’s power can be made manifest in you.
John 9:2-3 And his disciples asked him, saying, Master, who did sin, this man, or his parents, that he was born blind? Jesus answered, Neither hath this man sinned, nor his parents: but that the works of God should be made manifest in him.
Don’t beat yourself up over things, just go to the Lord and ask His forgiveness and His help. He is more ready to forgive you for shortcomings than you probably are yourself. He loves you, and that’s forever!