“Between a rock and a hard place” means “to make a difficult decision between two things that are equally unpleasant”. Example: I’m between a rock and a hard place. If I go with Susie, it’ll be much more expensive and if I go with Julie, Susie won’t.
Idiom of the day: Put your cards on the table. Meaning: To tell honestly what you think or what you plan to do. Example: She thought it was time to put her cards on the table and tell him that she had no intention of marrying him.