The best thing you can do for others you care about that don't necessarily care back about you is make give them gifts that they dont know. Wish the best for them, make du'a for their dreams to come true and secretly continue in helping them however possible. Let al-Wadud fill the void in your heart with His endless love and let Ash-Shakur, the most appreciative reward you and validate your sincere selfless deeds that you do.