My thoughts exactly. When doubt arises call it like it is, we all know that God does not cause doubt, satan continuously tries to steal our faith. He came to kill, steal and destroy. God comes to give life!
I'll be praying for you Donna. I just want to add, that you can still use your natural protocols. They don't mean you don't have faith. The very opposite actually, because God gives us wisdom as to what to take into our bodies for good health.
Seek God through this, be in prayer and let the Holy Spirit guide you into all truth and by all means stand firm on the Word of God!