I don't know if I am cursed or something. If I sell a coin now from airdrop/bounty few days later that coins increases much that you will regret selling. If I hold a coin from airdrop/bounty again that coins price decreases much that you will regret not selling right away. I'm confused now whenever I sell the price increases and when I hold the price decreases. Am I cursed?

No and i believe its not just you, many people and also myself feel that way, i believe its just miss decision. I know its hurt and it also became a regret but i do think its good thing to learn and that how crypto market is.