Stuck in the Middle — Virginia Smith

Joan Sanderson's life is stuck. Her older sister, Allie, is starting a family and her younger sister, Tori, has a budding career. Meanwhile, Joan is living at home with Mom and looking after her aging grandmother. Not exactly a recipe for excitement. That is, until a hunky young doctor moves in next door. Suddenly Joan has a goal--to get a date. But it won't be easy. Pretty Tori flirts relentlessly with him and Joan is sure that she can't compete. But with a little help from God, Allie, and an enormous mutt with bad manners, maybe Joan can find her way out of this rut.
Book 1 of the Sister-to-Sister series, Stuck in the Middle combines budding romance, spiritual searching, and a healthy dose of sibling rivalry.