Ah but that is just it - you are not obedient to God!
The Bible instructs us to not fear even in the valley of the shadow of death.
You disobey that instruction. Evidently because you don’t believe God is with you. For if you did as David said you would not fear!
Psalms 23:4 Yea, though I walk through the valley of the shadow of death,
I will fear no evil: for thou art with me; thy rod and thy staff they comfort me.