One is only helpless (unable to defend oneself or to act without help) when one lacks abilities and skills.
Critical thinking skills and an ability to acknowledge a remarkable concurrence of events or circumstances without apparent causal connection will maintain a solid mental state. An ability to make clear, reasoned judgements.
On the flip side, a negative parenting environment, lack of education, limited opportunities, limited rewards… Combined with rationalizing (justification or false beliefs)—will ruin you utterly—leave you “helpless” to varying degrees.
The opposite of helplessness is:
Ability, aptitude, capability, capacity, cleverness, competency, dexterity, efficacy, efficiency, energy, expertness, faculty, force, might, power, qualification, readiness, skills, strength, susceptibility, talent