People generally find things easiest when they like the subject matter and therefore have the motivation to read well beyond and around the syllabus. Musicians and artists are classic examples where if one has the dexterity and creative ability, the subjects are more of a hobby than work but completely unapproachable and impossible to others without that innate ability.
I believe far more is said about a persons character when they struggle with a subject at length but then still manage to overcome the difficulties to finally succeed. It shows tenacity, determination and resilience - all qualities highly valued by employers and as a philosophy for life in general.
OP. don't fret. Very often, going back repeatedly to basics and first principles will provide new insight into problems you thought were impossible. Try looking at things from a different perspective.
For instance with circuits and electricity, try making analogies with water pressure and the flow of water in pipes etc. This often helps with conceptual understanding.