You probably have less power and control than you think over many big issues. And you have more power and control than you realize in the day-to-day moments in your ordinary life. Therefore, commit to living your days - your actions and interactions - with kindness, patience, courage, and presence. Commit to living with integrity, being true to your highest self, attentive to your motives in your conversation and actions. This will have far more influence than you realize.
(This will lead you out of a sense of hopeless and despair about global issues - or a vague fantasy of being a savior without any practical steps to match - and will help you listen and discern for where you can contribute and be the most effective.)