My question is how could one tell when they are being inspired by a higher power vs just using the power of ones own mind. Could these two things not oftentimes overlap? Also could a higher power (as wise as they may be) also not be wrong at times?
They indeed do overlap. The further details of the spiritual nature of each urge and inclination, are understood when one advances deeply spiritually via initiation, progressing in both meditation and self knowledge, which helps over time for someone to clear out what is from one's self and what is from the Gods.
The Gods do not only exist as external beings and essences, we are literally their progeny and we have them also "within". This is from where Abrahamism took the "From my image you were created". The origin of this was from Babylonian tablets, which said the same thing; how the Gods or the Annunaki, descended upon Earth and created humanity in their "image".
As this is multidimensional, you must study the JoS and pray to the Gods to unveil it slowly for you, and it will start unveiling as you also self-discover.