Project for my nursing leadership class.

Scenario:
You have completed your first year as a nurse on a 17-bed orthopedic floor. During this period, you have changed your schedule several times at the request of your manager. You were hired to work three 12 hour shifts, but now you are working five 8 hours. In addition, your shifts rotate monthly (day-evening-night). Since your fourth month on the unit, you have been asked to assume charge nurse duties. You arrive to work in a timely fashion and complete your tasks. But because you are shy, you avoid personal conversations. Your co-workers described you as quiet and a bit distant. One evening the nurse manager hands you a performance appraisal form and asks you to complete it by the next day. This is your first performance appraisal and you know nothing about it. You attempt to complete it, but you are unclear about how to answer the questions. The next day, your manager asks you to come to her office to discuss your performance thus far. During the discussion, the manager identifies that you have been described as distant and unapproachable by your co-workers. The manager continues by telling you that immediate improvements are necessary for you to remain in your position. You are stunned. The nurse manager has never mentioned problems with your job performance before this moment. You sing the appraisal at the manager's request because you do not want to appear difficult. What should you do next?