First of all, you need to relax and read something enjoyable that is not pathology.
If, after you have read a non-medical fiction book, spent time with friends and family, traveled, and just overall enjoyed life, and you still feel the burning desire to read before residency then I would recommend:
1. Lester Manual of Surgical Pathology to give you an idea of how to gross
2. Some kind of basic histology book (Wheater's, Histology for Pathologists etc) to know what normal tissue looks like.
You can always try to learn a little about what immunos go with what, learn a little about ajcc staging and cap checklists, and try to review some clinical stuff, but you don't need to overdo it.