If you or a loved one have received one of those health diagnoses, I know what you're going through. I've just found out I have cancer. After hearing the prognosis, I turned to God, asking Him to help me genuinely believe what I say I believe: that He is with me and will guide me every step of the way. That, and constant prayer have allowed me to sleep well at night. Well, most nights.
There have been times where fear has kept me awake, worried, angry, and hurt' why me? I allow myself to sit in that hurt for a bit, because it's okay to not be okay. In those moments, I lean on God's word, believing that "weeping may endure for the night, but joy comes in the morning." I believe our faith is like a muscle: the more you pray, listen to praise music, and read your Bible, the stronger your faith is. Growing that faith helps you to believe what you say you believe: that God is with you, He is for you, and He will see you through.
So, if you are struggling with your health, I pray: may God, the Great Physician, bring healing to us both as we walk through this journey.