The Fallback Plan, by Leigh Stein

Wildly depressing quarter-life crisis novel. Esther Kohler had a depressive breakdown during her last semester of college, and has since returned to live with her parents. She spends her days taking prescription pills and smoking pot with a pair of loser-type guys she's known all her life, and then takes a job as a nanny for a couple whose youngest daughter died of SIDS. Esther has an affair with the father, feels terrible for the mother, and at the end, has a bit of what seems to be a breakthrough, but the whole of it, despite being wonderfully written, was too glum for a bright yellow cover. Also, when writing about depressed women in their 20s named Esther, be careful- inviting comparisons with The Bell Jar is bold, but not wise.