New Delhi, Nov. 10 -- After weeks of shopping, planning and family get-togethers, the Diwali season has come to an end. There was plenty of laughter, food and family time, and I should be basking in a lovely post-festive glow. Instead, I'm feeling rather miserable. The thought of returning to normal life feels inexplicably depressing. I'm missing the people who were here, the plans we made, and most of all, the excitement of having something to look forward to.

Apparently, I'm not alone. For Mumbai-based entrepreneur Ritika Basu, the first sign of post-festival blues is irritability. "Little things that wouldn't normally bother me suddenly get under my skin," she says. "There's this unsettling feeling of emptiness as though something imp...