Just because we sincerely try to live the way God wants us to doesn't mean we will be exempt from life's trials and sorrows. We are still part of the human race, and we suffer illness and pain just like everyone else. Jesus said that God "sends rain on the righteous and the unrighteous" (Matthew 5:45).
In other words, we often don't know why God allows things like this to come into our lives. But God is sovereign, and even when life turns against us He still can be trusted. He hasn't turned His back on you, nor is His love for you any less. After all, His Son suffered far more than you and I will ever suffer, when He took all our sins and judgment upon Himself and died on the cross for us.
The key issue isn't why God allows bad things to happen to us, however, but how we will react to them. Will we react with fear or anger or resentment or will we react with faith and trust and peace? My prayer is that this will be a time when you draw closer to God, and you find in Him the strength and calmness you need. The Bible says, "You will keep in perfect peace him whose mind is steadfast, because he trusts in you" (Isaiah 26:3).
Make sure of your commitment to Christ. Then thank Him that He is with you, and ask Him to help you trust your life into His hands every day. No matter what the future holds for us, when we know Christ we are safely in His care forever.