Is it forbidden to feel wonder at God's existence and His knowledge of the unseen and His forgetfulness, and does it lead to psychological illnesses?

Whispers [waswasah] and self-talk are forgiven by Allah as long as they are not acted upon or spoken. Disliking them is a sign of sound faith. One mustDistance oneself from these whispers and engage in abundant supplication [dua] and remembrance [dhikr]. As for the existence of Allah, it is the clearest of realities, and the proofs of His existence are manifest in the universe and in the very creation of man himself, for every created thing has a Creator. Allah's knowledge of the unseen is comprehensive; He knows everything, including what a leaf or a grain falls, and He sees everything, and comprehends the secret counsel of three and five.